Biochemistry PDF

PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 1 CHAPTER 1 INTRODUCTION TO BIOCHEMISTRY Biochemistry deals with chemical or metabolic processes which take place in tissue cells. These metabolic reactions take place in the...

PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 1 CHAPTER 1 INTRODUCTION TO BIOCHEMISTRY Biochemistry deals with chemical or metabolic processes which take place in tissue cells. These metabolic reactions take place in the material called protoplasm which is the basis of all forms of life. As long as these reactions take place in an organized form, we remain healthy. The moment there occurs disorganization in these reactions; we fall ill or even die. It is amazing to note that all the elements that collectively give rise to living organisms are by themselves inanimate. However, when present in optimum amounts and in optimum combinations, they make life possible. An Urdu poet (Birj Narayan Chaksbat), a non-scientist, has best illustrated this in the following verse:- Compared to other biological sciences, biochemistry is quite young. This is because investigators in this field had to wait for developments to take place in other branches of chemistry, i.e. inorganic, organic and physical. It is only in the second half of the twentieth century that biochemistry that started as an offshoot of physiology emerged as an independent discipline. In 21 st century it is one of the most dynamic sciences whose frontiers are expanding at a fantastic rate. This great leap forward in biochemistry has been of enormous help in providing explanations for the mechanisms of many physiological processes which were hitherto unknown or were shrouded in mystery. Other medical sciences, i.e. physiology, pharmacology, bacteriology and Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 2 pathology and even therapeutics have also greatly benefited from new discoveries in biochemistry. All these medical sciences have contributed to the great strides made in medicine and a major part of the credit goes to biochemistry. Biochemistry has assumed an increasingly important role in various branches of medicine and biochemists have frequently been called upon to provide the special techniques and knowledge to the solution of clinical problems. Biochemical investigations can lead quite directly to the suggestion of remedies. For example, the discovery of specific biochemical deficiencies in rickets, pellagra, beriberi, scurvy and pernicious anemia led rapidly to the successful therapy by a rational method. The biochemist has provided vitamins and hormones in pure conditions and has aided in the preparation of vaccines, antitoxins, sera, etc. The fields of enzyme inhibitors, recombinant DNA technology, genetic engineering, gene mapping, DNA profiling and cloning have opened a new era in medicine. Last, but not the least, he has provided a large number of chemical tests as aids in the diagnosis of diseases. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 3 CHAPTER 2 CARBOHYDRATES Definition The definition of the carbohydrates is given as: ―carbohydrates are polyhydroxy aldehydes or ketones or their complex substances which on hydrolysis give polyhydroxy aldehydes or ketones‖ The carbohydrates are the organic compounds. They are made up of carbon, hydrogen, oxygen. The literally meanings of carbohydrates are the hydrated carbons. Carbohydrates also called sugar‖ General formula As the carbohydrates are the hydrated carbons so the no. of water molecules attach to the carbon are equal in number to the no. of carbon atoms. Thus the general formula is given as Cn (H2O) n. here ―n‖ is the whole number. Exception to the general formula and definition There are some such carbohydrates which contain nitrogen, phosphorous or sulphur also in addition to carbon. Rhamnose has a Formula C6H12O5. Also all the compounds having formula Cn(H2O) n may not be carbohydrates formic, acetic and lactic acids are some examples of such compounds. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 4 Characteristics of carbohydrates In general carbohydrates are white solids, sparingly soluble in organic liquids but except for certain polysaccharides are soluble in water. Many carbohydrates of low molecular weight have a sweet taste. Functional groups of carbohydrates The carbohydrates have two major categories on the basis of functional group. Two functional groups. Aldehyde group: ―-CHO‖ it is on the first carbon and the carbohydrate with aldehyde group is called aldoses (aldose suger) Keto group: O || R-C-R is on the second carbon, the sugars with ketonic group are called ketoses (keto-suger) Source of carbohydrates Carbohydrates are the natural compounds and their basic source is plants. The chief source of carbohydrates is the cereals. Starch is the abundant in the cereals. The other source of carbohydrates is: (i) Vegetables: e.g. potato, carrot, beats etc. (ii) Legumes: e.g. peanut, lenticle etc. (iii) Fruits: both sweet and non-sweet fruits provide carbohydrates. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 5 Chain or cyclic structure of carbohydrates Carbohydrates are both in cyclic forms and chain forms and they both forms are in equilibrium state. Straight chain carbohydrates → Cyclic carbohydrates 1 H― C= O 2│ H― C― OH 3│ HO― C― H 4│ H― C― OH 5│ H― C― OH 6│ CH2OH OH Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 6 Occurrence of carbohydrates Carbohydrates are the 2nd most occurring substance in nature after water. The surprising quantity of carbohydrates can be known by considering the point that cell wall of all plants made up of cellulose 50-80% of dry weight of plants is due to cellulose. Natural production of carbohydrates The carbohydrates are prepared by the plants by the process of photosynthesis. The photosynthesis involves the following reaction. CO2 + H2O –––––→ C6H12O6 + O2 Carbohydrates Major source of energy Carbohydrates are the macronutrients as 55% of our daily calories come from carbohydrates. 1g of carbohydrates provides 4 cal. ―when the molecules are oxidized so produced a high amount of energy ― this is the principle used by carbohydrates to give energy. The process of oxidation of carbohydrates (also all other nutrients) is called respiration. The reaction involve in respiration C6H12O6 + O2 ––––––→ CO2 + H2O + E Glucose Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 7 How carbohydrates supply energy The simple sugars are absorbed directly by the small intestine into blood stream. But the disaccharide and polysaccharide do not absorbed in blood directly first convert into monosaccharide. This bond breaking also provides energy. Then the monosaccharides are absorbed by blood. Function of carbohydrates in animal body The carbohydrates form the following major role in the living body.  Construction of body organs.  Assist in body’s absorption of calcium.  Helps in lowering cholesterol level.  Provides nutrients to the friendly bacteria in digestive track that help in digestion.  Balance water-mineral balance. Sweetness in carbohydrates Carbohydrates who has lower molecular mass are sweet in taste as the complexity and molar mass increases the sweetness decreases. In fruits the sweetness very from time to time sweetness increases as fruits ripen e.g. banana and apple b/c during ripening the starch converted to simple sugar. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 8 Classification of carbohydrates The carbohydrates are classified into three groups. (i) Monosaccharide : having one sugar molecule and cannot hydrolyze to smaller units (ii) Disaccharide: Having two sugar molecule and give two monosaccharide on hydrolysis. (iii) Oligosaccharides: Having 3-10 sugar molecules. on hydrolysis yield 3-10 monosaccharides. (iv) Polysaccharide: having more than ten sugar molecules and give disaccharide on hydrolysis and on further hydrolysis the monosaccharide are met. Monosaccharide Mono ------------------one Saccharides--------------sugar 1. They are sweet in taste. 2.It cannot further hydrolysis. 3.Generally they are water soluble. 4. Two types of functional group are present in it. i) Aldehyde group: (–CHO) ii) Keto group: O || R-C-R Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 9 Classification of monosaccharide Monosaccharide can be classified on the basis of functional group i) Aldose ii) Ketose Aldose i) Glucose: (C6H12O6) It is also called grape sugar. It is widely distributed in nature. It combines with other sugars to form important disaccharides such as sucrose, maltose, and lactose. It is commercially obtained from starch. It is the main sugar of human body. Normal blood glucose level of human in fasting 80_100mg% and in random is 100__120mg%. Glucose is also called dextrose. ii) Ribose: iii) Erythrose: iv) Glucoheptose: Ketose i) Fructose: (C6H12O6) The most common source of fructose is sucrose. It is sweetest of all the sugars. Pure honey contains fructose. It is present in appreciable amount in seminal fluid and act as source of energy for spermatozoa. ii) Erythrulose: iii) Ribulose: iv) Sedoheptulose Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 10 Disaccharides Definition: Having two sugar molecules, give Two monosaccharide on hydrolysis Disaccharides occur naturally. They are less sweet than monosaccharide. The two monosaccharide units with glycosidic linkage they are white crystalline solids. They are soluble in (H2O) water.Their molecular mass greater than monosaccharide. Classification of disaccharides Homogeneous If all sugar molecules in disaccharides are same it is called homogeneous disaccharides.e.g. maltose. Heterogeneous If all sugar molecules are different in disaccharides called heterogeneous e.g. sucrose. Examples of disaccharides Sucrose. (Glucose + fructose) It is also called saccharine. It is a common table sugar. Lactose. (Glucose + galactose) It is also called milk sugar. Maltose. It is composed of two monosaccharide (glucose + glucose) It is also called fruit sugar. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 11 Oligosaccharides On hydrolysis these sugars yield three to ten monosaccharide units. Not important physiologically. Polysaccharides Definition Having more than ten sugar molecules and give disaccharides on hydrolysis and on further hydrolysis the monosaccharide are met. Many saccharides join to form poly saccharides. They are tasteless and not optically active Classification of polysaccharides There are two types of polysaccharide. (i)Homopolysaccharides: The polysaccharides which yield one type of monosaccharide on hydrolysis is called homopolysaccharides.e.g Starch , Glycogen (ii) Heteropolysaccharides: The polysaccharides which yield different types of monosaccharide on hydrolysis called heteropolysaccharides.e.g Mucilage’s, Hemi cellulose Examples of polysaccharides Cellulose: Most abundant on earth present in cell wall of plants. Starch: It is stored food material in plants, in corns, grains etc. Glycogen: It mainly occurs in animal muscles and liver. Starch: It occurs in grains, seeds and tubers Types : (i) Amylose (ii) Amylopection Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 12 CHAPTER 1 LIPIDS INTRODUCTION LIPO MEANS FAT Definition The lipids are organic substances occurring in plant and animal tissues belong to a very heterogeneous group of compounds related to fatty acids. Lipids include fats, oils, waxes, steroids, & defined as substances having the following properties: 1. They are insoluble in water (hydrophobic) but soluble in non-polar solvents (ether, chloroform, benzene). 2. Their primary building blocks are fatty acids, glycerol, sphingosine and sterols. 3. In most cases, they can be utilized by the living organisms. Most common lipid is fat in animals & plants 4.Lips used to store energy because of higher proportion of C-H bonds and very low proportion of oxygen , oxygen store double the amount of energy as compared to the same amount of any carbohydrates CLASSIFICATION OF LIPIDS These are classified as, I. Simple Lipids II. Compound Lipids III. Derived Lipids SIMPLE LIPIDS This class includes fats oil & waxes. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 13 FATS AND OILS These are esters of fatty acids with glycerol. (Trihydroxy alcohol). They are known as triglyceride or triacylglycerol or fat. A fat in liquid state called oil Fats & oils are lighter than water and have specific gravity of about 0.8 Glycerol+3Carboxylic acid -------→Triglycerides+3CO2+3H2O OR O || CH2-OH CH2-O-C-R | | O || CH-OH + 3 RCOOH → CH-O-C-R +3CO2 +3H2O O | | || CH2-OH CH2-O-C-R ( Glycerol) (carboxylic acids) (Triglycerides) WAXES Definition These are esters of fatty acids with long chain monohydric alcohols. RCOOH + ROH ―→ RCOOR + H2O Occurrence Waxes are widespread in nature as secretion of certain insects as protective coating of skin, e.g. honey bee wax, fur of animals, certain animal oil & whale largely composed of waxes. Human secretion (sebum wax) Sebum is a secretion of human skin having waxes. It helps skin to be moist and flexible. Plant waxes present in cuticle of plant cell. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 14 COMPOUND OR COMPLEX LIPIDS Definition These are esters of fatty acids containing groups in addition to an alcohol and fatty acids. These are sub divided as follows: 1. Glycolipids also called Glycosphingolipids These contain sphinogosine, fatty acid and a monosaccharide or an oligosaccharide unit. 2. Sulphosides These contain sphingosine, fatty acids, a sugar & a phosphate group. 3. Phospholipids These are lipids that contain an alcohol, fatty acid and phosphoric acid in addition they frequently have N-containing bases & other sustituents. 4. Lipoproteins These are complex of lipid with proteins. III. DERIVED LIPIDS These include fatty acids, glycerol, steroids, sterols, fatty aldehyde, lipid soluble vitamins, ketones etc. Fatty acids Definition Hydrolysis of fats is called fatty acid. Fatty acid contain long hydrocarbon chain bonded to –COOH Group. ―They are aliphatic monocarboxylic acids‖ Classification Fatty acid may classified as, Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 15 1.Saturated Fatty acids They do not contain double bond. ―Animal fat are usually saturated‖ Fats containing saturated fatty acids are solids at room temperature Example Butyric acid C3H7COOH 2.Unsaturated fatty acids They contain one or more double bond in their formula. Plant fats are mostly unsaturated. Fats containing unsaturated fatty acids are liquid at room temperature Types Monounsaturated fatty acids i.e. Oleic acid C18H33COOH Polyunsaturated fatty acids i.e. Archidonic acid C19H31COOH STEROIDS A large number of compounds found in nature occurring in nonsaponifiable fraction of lipids belong to the class of compounds called steroids. STEROLS A sub group of steroids is sterols which contain one or more –OH groups and no carbonyl and carboxyl groups; their names end in -ol. Examples Some of natural compound belonging to steroids are cholesterol, ergosterol, bile acids, male and female sex hormones and the hormones of adrenal cortex. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 16 CHOLESTEROLS It is most abundant animal sterol. It occurs in animal tissues most abundant in the adrenal gland followed by nervous system. Normal plasma level ranges from 150 to 220mg/dl. Some 140 grams of cholesterol may be present in an adult human being. It also present in plasma membranes of tissue cells & in plasma lipoproteins. FUNCTIONS OF LIPIDS Energy source They are good source of energy. Carrier of fat – soluble vitamins Lipid in food also acts as a carrier of fat-soluble vitamins and nutritionally essential fatty acids. Dietary Lipids The dietary lipids decrease gastric motility and have a high satiety value. Stability Body fat gives anatomical stability to organs like kidney. When a person loses weight rapidly, his kidney is liable to become floating kidneys. Good reservoir Fats are good reservoir in the body. Adipose tissue is best suited for this purpose due to its very little water content. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 17 Insulating Effect Lipids exert an insulating effect on the nervous tissue. Integral part Lipids are integral part of cell protoplasm and cell membranes. Precursor Some lipids act as precursors of very important physiological compounds.e.g. cholesterol is precursor of steroid hormones. CHAPTER 1 Proteins Definition The proteins are extremely complicated molecules and are nitrogenous compound made up of a variable no. of amino acids joined to each other by specific type of covalent bond called peptide bond or peptide linkage. Derivation The name protein derived from Greek ―protos‖ which means the first or the supreme. ―Proteins are polymers of amino acids‖ Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 18 General formula of amino acid H | R-C-COOH | NH2 Amino Acids have two characteristics functional groups the amino group _ NH2. The functional group _COOH which is Carboxylic group. R represents the side chain which varies from one Amino acid to other Most amino acid have one _NH2 group and other _COOH group but some have more than one of these. They are 20 amino acid which have been found to occur in all proteins and for which genetic codons exist. If R changes the amino acid changes structurally For Example If R is H H | H-C-COOH | NH2 GLYCINE If R is CH3 H | CH3-C-COOH | NH2 ALANINE Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 19 ―Amino acids are building blocks of proteins‖ Functions of proteins Proteins present in cytoplasm as well as the cell membrane of cells with out exceptions. Mammalian muscles contain 20% Blood plasma 7% Cows 3.5% Cereals 12% Beans, nuts, pulses, contain 20% proteins. Besides forming structural elements of body and important food constituents as well. They are also present in daily use articles such as silk, leather, and wool. A group of substances called enzymes which are biocatalyst of the body, ―Enzymes are mainly protein in nature.‖ Hormonal effect Many of the hormones which regulate the chemicals and other process or the body are also protein in nature. Structure of proteins Each type of proteins contains a specific number of amino acids, Different kinds of proteins have different shapes are related to their particular function in life processes. Proteins molecules have different several different level of structure. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 20 Primary structure of proteins Definition Linear sequence of Amino acids. Amino group is in one side and left hand side and carboxylic group on right hand side. Length Length is vary according to proteins, length of chain depend upon type of proteins which is under discussion. But it must be polypeptide long chain. No additional hydrogen bonding in primary structure of proteins and it is present in other structure. Only covalent bond is present in primary structure. HH H H | | | | -N-C-C-N-C- | || | HO CH3 Secondary structure Definition The regular arrangements of amino acid that are located near to each other in linear sequence these arrangements are termed as Secondary structure of polypeptide Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 21 Tertiary structure Definition The tertiary structure of a proteins means it’s over all three ―Dimensional shape‖ Complex secondary structure will take on three dimensional structures. In which there is folding, looping and binding of chain including all of its secondary structure. The final shape may be a globe or an irregular shape and is entirely determined by intermolecular forces and bond polypeptides chain form a complex structure known as proteins structure.e.g Myoglobin: It has been calculated that if the chain of myoglobin could be extended the length of its molecule would be 20 times its width. Quaternary structure Definition  Association of multiple polypeptides, not found in all proteins. The structure formed by aggregation of two or more polypeptide chain is called quaternary structure the aggregation of such polypeptides chain form one functional macromolecule. Each poly peptide chain is called subunit. e.g. Hemoglobin, Collagen etc. Biological role of Proteins Proteins have following some important role: Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 22 1. Proteins as structural material Proteins are the structural material for the plant and animal. Protein form the major part of dry weight of plant and animal protein are the major part of all the membrane system of cell. Proteins take an essential part in the formation of protoplasm which is the essence of all forms of life. 2. Energy source Proteins provide energy to body proteins is breakdown into amino acid during digestion the deamination of these amino acid take place. Ammonia is released and different compounds are formed. The compound enters into the respiratory pathway (glycolysis and Kreb’s cycle) at different points. 3. Defense of body Proteins are used against disease in higher animals. Antibodies and interferon are proteins in nature in they defend the body from attack of bacteria and viruses (immunoglobulin). Protein is an integral part of all viruses which are very important from a pathogenic point of view. 4. Dietary protein The supply of nitrogen and sulphur is regulated by dietary protein e.g. each one gram of dietary protein furnishes 4.1 kcal or 4100cal. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 23 5. Enzymes Some proteins act as enzymes, enzymes play important role in metabolic reaction, and they enter and speed up specific chemical reaction. 6. Hormones The hormones are protein in nature have great effect a metabolic and reproduction. 7. Reserve food Most part of fruits and vegetables is composed of proteins. Thus proteins are as storage composed e.g albumin is stored in egg white casein present in milk. Certain proteins are present cell membrane bind vitamin hormones etc. to mediate the cellular action. 8. Contractility Most proteins are involved in contractility e.g. dyne in cilia and flagella. Tubulin in spindle fibres. Actin and myosin in muscles. 9. Exchange of gases They execute their activities in the transport of O2 and CO2 by hemoglobin. Some act as hormones e.g. insulin, growth hormones and parathyroid hormones etc. Muscles proteins have a role in contraction of muscle fibres.e.g Antarctic fish contain antifreeze proteins which protect their blood from freezing. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 24 Homeostatic control The function is the homeostatic control of volume of the circulating blood and that of the interstitial fluids through plasma protein. Plasma proteins take part in blood coagulation and transport of substances such as hormones drugs, metal like iron and copper. Blood clotting They are involved in blood clotting through thrombin fibrinogen and other protein factors. The proteins present in blood plasma act as a colloidal particles and exert and osmotic pressure of 25_30mmHg. The role of proteins in the plasma membranes where they act as transporting or carrier molecules and receptors. Heredity transmission They perform hereditary transmission by nucleoproteins of the cell nucleus. Chromosomes movement Movement of organs in plant cells is due to movement of chromosomes. During anaphase of cell division Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 25 CLASSIFICATION OF PROTEINS Proteins have been classified in several ways. The following classification is based upon physicochemical properties of proteins. A protein may belong to one of the three types, i.e. I. Simple proteins. II. Compound or conjugated proteins. III. Derived proteins. SIMPLE PROTEINS On hydrolysis, these proteins yield only amino acids or their derivatives. These consist of the following types. 1. Albumins: These are water-soluble proteins and occur in both plant and animal kingdoms. Examples are serum albumin, ovalbumin and lactalbumin m animals and legume in plants. 2. Globulins: These are insoluble in water but soluble in dilute salt solutions and are heat- coagulable to a variable extent. They are found in animals, e.g. lactoglobulin, myosin in muscle, ovoglobulin, serum globulins and also in plants, e.g. legumin. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 26 3. Globins These are rich in histidine but are not basic. They unite with heme to form hemoglobin. Hemoglobin of different species differs only with respect to globin, but the heme part is the same in all cases. 4. Prolamins These are soluble in 70 to 80% ethanol but are insoluble in water and absolute alcohol. Examples are gliadin of wheat and zein of maize. These are rich in the amino acid proline but deficient in lysine. 5. Histones These are very strongly basic proteins as they are rich in arginine. In combination with deoxyribonucleic acid (DNA) they form nucleoproteins (nucleohistones). The association of DNA and histones gives rise to complexes called nucleosomes. 6. Protamines These are present in sperm cells like histones; they form nucleoproteins with nucleic acids and are rich in arginine. These proteins lack in both tyrosine and tryptophan. 7. Albuminoids These are also called scleroproteins [sclero = hard] and occur only in animals; they do not occur in plants. These proteins includes i) Collagen ii) Elastin iii) Keratin Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 27 COMPOUND OR COUNJUGATED PROTIENS In these molecules the protein is attached or conjugated to some non – protein groups which are called prosthetic groups. The following types of proteins belongs this group. i) Nucleoproteins. ii) Phosphoprotien iii) Lipoproteins iv) Carbohydrate - containing proteins v) Chromoproteins vi) Metalloproteins DERIVED PROTEINS This class of proteins includes substances which are derived from simple and conjugated proteins. These proteins are sub divided into primary and secondary derived proteins. i) Primary derived proteins: These are synonymous with denatured proteins. Denaturation takes place when some or all of the cross -linkages which normally keep the molecular structure of protein intact are split. ii) Secondary derived proteins: These substances are intermediate formed in the progressive hydrolysis of protein molecule. The are of different sizes and different amino acid composition and are roughly grouped according to their molecular size into a) Proteoses b) Peptones c) Peptides d) Polypeptides e) Oligopeptides Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 28 AMINO ACIDS INTRODUCTION ―Amino acids are the building blocks of proteins‖ Amino acids are the monomer of a bio-polymer which is called as proteins. They form protein by a biochemical bond called Peptide bond or peptid linkage. Various number of amino acid joins to one another with peptide bond to form ―protein‖. There are twenty different kinds of amino acids but with Different combination they form different kinds of protein. STRUCTURE Amino acid has very simple structure. It contain a central alpha carbon (The carbon attached with the functional Group is called alpha carbon). H | NH2 -C-COOH | R There are present an acidic group on one side and an amino group on other side of alpha carbon. Hydrogen is present on alpha carbon with a R group. The R group may vary to produce different types of Amino acids. It means the kinds of all amino acids depend upon the nature of R group. So comprehensively we can say that (except glycine) all the amino acids. Contain following unit with alpha carbon. 1. R group 2. carboxylic group(_COOH) 3. Amino group (_NH2) 4. Hydrogen atom (_H) Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 29 2. AMINO ACIDS OCCURRING IN PROTEIN MOLECULES (STANDARD AMINO ACIDS) Although more than 300 naturally occurring amino acids are known, but only twenty amino acids take part in the formation of all types of proteins, plant as well as animal in origin. These twenty amino acids are called primary, standard or normal amino acids. H H | | H-C-COOH CH3–C-COOH | | NH2 NH2 GLYCINE ALANINE Classification of Standard Amino Acids This is based upon the type of side chain, i.e. R group present because it is the side chain which gives distinctive properties to amino acids. 1-Amino acids with non-polar aliphatic side chains These include glycine Alanine, Valine. Leucine and Isoleucine. 2. Amino acids with aromatic side chains These include phenylalanine tyrosine and tryptophan and are said to be relatively polar. 3. Side chain containing hydroxyl (-OH) group These include serine and threonine. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 30 4. Amino acids with side chains containing sulfur (S) atom These include cysteine and methionine. 5. Amino acids with acidic side chains These include glutamic acid and aspartic acid; 6. Amino acids with basic side chains These include lysine, arginine and histidine. 7. Amino acid The only example of this type is proline. NON-STANDARD AMINO ACIDS The non-standard amino acids are those amino acids which, contrary to the standard amino acids already described, do not take part in protein synthesis but many of them play important role in the body. There are several hundreds of such amino acids, a few of which having important physiological functions are given below. 1. Citrulline 2. Ornithine 3. Argininosuccinic acid 4.β-alanine It is a part of the molecule of a vitamin namely pantothenic acid. 5. Pantothenic acid It is a widely distributed vitamin; it forms a part of the of coemzyme A (abbreviated as CoA-SH or just CoA) which takes of metabolic reactions. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 31 6. γ – Amino- Butyric Acid (GABA) It occurred in brain and other tissues it has an important physiological role as neurotransmitter. 7. Dihydroxyphenylalanine It is formed in tissues during the metabolism of phenylalanine and tyrosine. L- Dopa is being used in treating Parkinsonism as in the brain it give rise to dopamine which is a neurotransmitter. 8. Homocysteine 9. Iodinated amino acids These are mono - iodotyrosine (MIT), di-iodotyrosine (D1T), tri- iodothyronine (T3) and tetra-iodothyronine (T4). The last two are thyroid hormones, Functions of Amino acids ―Amino acids are building blocks of Proteins‖ So all the functions which proteins perform are the function of amino acids i) Proteins are present in cytoplasm as well as in the cell membrane of cells with out exceptions. ii) Beans, nuts, pulses, contain 20% proteins. iii) Besides forming structural elements of body and important food constituents as well. They are also present in daily use articles such as silk, leather, and wool. iv) A group of substances called enzymes which are biocatalyst of the body, ―Enzymes are mainly protein in nature. v) Hormonal effect. Many of the hormones which regulate the chemicals and other process or the body are also protein in nature. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 32 vi) They play role as:  Hormone biosynthesis  N2 metabolism  Tolerance of certain environmental stresses e.g. Proline stores under salt stress condition in plants NUCLEIC ACIDS INTRODUCTION Nucleic acids were first demonstrated in the nuclei of pus cells in 1869 and in sperm heads in 1872 by a Swedish doctor Friedrich Miescher and named as nucleon. Nucleic acids are present in every living cell as well in viruses and have been found to be the essential substance of the genes and the apparatus by which the genes act. Two types of nucleic acids Deoxyribonucleic acid. i.e. DNA Ribonucleic acid. i.e. RNA. COMPONENTS OF NUCLEIC ACIDS Both DNA and RNA are formed by joining together of a large number of nucleotide units or mononucleotides, each of which is a nitrogenous base- sugar-phosphoric acid complex. In other words, nucleic acids are polynucleotide. Nitrogenous bases These are aromatic heterocyclic bases and include purine and pyrimidine derivatives. Purines - These include adenine and guanine, which are abbreviated as A and G respectively. Pyrimidines-These include cytosine, uracil, thymine abbreviated as C,U.T respectively. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 33 Mononucleotides- In nucleotides, a phosphoric acid molecule forms an ester linkage with one of the hydroxyl groups of the sugar of a nucleoside, Nucleotides- A nucleotide is a nucleoside phosphate. Nucleoside- The combination of a Nitrogen Base and 5-Carbon Sugar SOME OTHER BIOLOGICALLY IMPORTANT NUCLEOTIDES Nucleotides which are not combined in nucleic acids are also found in tissues. They have important special functions. Some of these compounds are given below. Derivatives of adenine ATP, ADP and AMP - ATP has two high energy phosphate bonds. NAD+, NADP+, FAD and coenzyme A. Characteristics of RNA and DNA Characteristics RNA DNA i. Nitrogenous base (a) Adenine and Guanine Adenine and Guanine Purines (b) Pyrimidines Cytosine and Uracil Cytosine and Thymine 2. Relative amounts of Highly variable A is always equal to T and complementary bases G is equal to C. Total purines = Total pyrimidines(Chargaffs law). 3. Sugar (as p- Ribose 2 -Deoxyribose furanoside form) 4. Phosphoric acid Present Present 5. Location in the cell Mainly cytoplasm; some Mainly in the nucleus; in the nucleus some in the cytoplasm (mitochondria) 6. Molecular weight Much smaller than DNA Much larger than RNA; 7, Molecular shape. Single-stranded which Double-stranded forming a may be coiled on itself double helix; and in certain cases has double helix parts. Rarely double stranded RNA has also been found even in humans. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 34 RIBONUCLEIC ACIDS (RN As) There are three main types of RNA Messenger or mRNA Transfer or tRNA Ribosomal or rRNA. It is estimated that tRNA forms 10 to 15%, mRNA 5 to 10% and rRNA 75 to 80% of the total RNA of the cell. mRNA encodes the amino acid sequence of one or more polypeptides specified by a gene or set of genes. tRNAs read the information coded in the mRNA and transfer the appropriate amino acids to a growing polypeptide chain during protein synthesis. rRNAs are constituents of ribosomes that synthesize proteins. RNA is a polsynucleotide, i.e. it contains a large number of nucleotides in its molecule. The nucleotides forming RNA consist of the following components:- 1. A nitrogenous base which may be either a purine (adenine or guanine) or a pyrimidine (cytosine or uracil). 2. Ribose which actually is D-ribose. 3. Phosphoric acid. DEOXYR1BONUCLEIC ACID (DNA) DN A contains the genetic information that gives rise to the chemical and physical properties of living organisms The nucleotides in DNA are linked to each other in the same way as in RNA. However unlike RNA, DNA is a double-stranded molecule or a double helix and sugar present in it is 2'- deoxyribose. Moreover DNA has the pyrimidine thymine and not uracil. Shape of DNA molecule : Watson and Crick in 1953 hypothesized that the DNA molecule is a double helix. The double helix of DNA (nicknamed as coil of life) can be visualized as a spiral staircase wound around a cylindrical axis. The bases are on the inside of the helix and the deoxyribose and phosphates on the outside. The helix in most of the DNA is of right handed type, i.e. the helix rises towards the right. Double helix of DNA. A and B represent major and minor grooves respectively. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 35 In DNA there are actually two antiparallel long molecules(each made up of a very long polydeoxyribonucleotide chain) which are wound on each other.These two chains are joined to each other throughout the whole length of the molecule through their respective nitrogenous bases. In this joining together a purines only joins with pyrimidines. The helical structure repeats at intervals of 3.4 nm and therefore there are. 10 base pairs in each completed helixThe helix is 2 nm in diameter. The molecule shows a minor groove and a major groove. Double helix of DNA A & B represents major & minor grooves respectively. BIOLOGICAL ROLE OF DNA DNA is the ultimate carrier of heredity in all eukaryotes and even most prokaryotes except certain viruses and phages. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 36 Genes are composed f DNA in which the genetic information is contained in the form of codes. The double helical structure of DNA.explains many of the properties of DNA. DNA has two important properties; to store genetic information and replicate, i.e. to synthesize double-stranded DNA exactly similar to the DNA originally present and to produce mRNA (transcription) which will dictate the synthesis of proteins Hormones Hormones These are chemical substances which are secreted into the body fluids by one cell or a group of cells and have a physiological control effect on other cells of the body. ENDOCRINOLOGY This is the science concerned with the structures and functions of the endocrine glands and the diagnosis and treatment of the disorders of the endocrine system. Functions of hormones 1. Help to control the internal environment by regulating its chemical composition and volume. 2. Transport substances through the cell membrane. 3. Play a key role of growth and development. 4. Contribute to the basic processes of reproduction, Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 37 Fertilization, nourishment of the embryo, and delivery of newborns. 5. Regulate metabolism and energy balance in the body. Types 1. Local hormones: These have specific local effects on the body. Example: Acetyl choline, secretin and Cholecystokinin. 2. General hormones: These affect body cells far away from their points of secretion. A few general hormones affect all the cells of the body, such as growth hormone and thyroid hormone. On the other hand, some hormones affect only on target cells because they have specific receptors for the hormone. e.g. ACTH, estrogen, and progesterone. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 38 CLASSIFICATION OF HORMONE BASED ON THE CHEMICAL NATURE 1. Peptides Anterior pituitary hormones - GH, ACTH, prolactin Posterior pituitary hormones - ADH, oxytocin Islets of langerhans - Insulin, glucagon, somatostatin Thyroid gland - calcitonin Parathyroid gland - parathyroid hormone Hormones of the GIT, i.e substance P Releasing and inhibitory hormones of the hypothalamus Ovaries - relaxin 2. Glycoproteins HCG, TSH, LH, and erythropoietin 3. Steroids (Cholestrol derivatives) Adrenal cortex (aldosterone, cortisol adrenal androgens) Ovaries (estrogen and progesterone Testes (testosterone) Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 39 4. Aminoacids (Tyrosine derivative) Thyroid gland - T3 - T4, 5. Amines (Tyrosine derivatives) Acetylcholine, epinephrine, Nor-epinephrine and melatonin. GROWTH HORMONE (GH) Human growth hormone is a hormone of the anterior pituitary gland and is also known as somatotropin or somatotropic hormone (STH). Its basic function is to cause body cells to grow. Nature GH is a small protein (peptide) Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 40 Functions of GH 1. Effects on protein metabolism: a) GH has predominately anabolic effects on skeletal and cardiac muscles. It stimulates the synthesis of protein , RNA and DNA. b) It promotes aminoacid entry into cells, as does insulin. c) It decreases the catabolism of protein because G.H mobilize free fatty acids to supply energy. 2. Effects on carbohydrate metabolism: (Hyperglycemia) GH is a diabetogenic hormone. Because of its anti-insulin effect, GH has a tendency to cause hyperglycemia. 3. Effects on fat metabolism the: a) GH has an overall catabolic effect in adipose tissue. It stimulates the mobilization of fatty acids from adipose tissue, leading to decreased triglycerides content in fatty tissue and increased plasma levels of fatty acids and glycerol. d) Fatty liver: This occurs due to excess mobilization of free fatty acids from adipose tissue. 4. Effects on inorganic metabolism: a) GH increase the retention of the phosphorus and Ca++ in body fluids by increasing absorption from the GIT and renal tubules. b) It also causes the retention of Na+, K+, Cl‾ and Mg++. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 41 5. Effects on bone, cartilage, and soft tissues: a).It acts on cartilage and bone, stimulating growth. b) Increases the deposition of connective tissue. c) Increases the thickness of skin. d) Increases the growth of viscera (liver, kidney) etc. e) Increases milk secretion in lactating animals. OXYTOCIN Introduction This is a hormone of the posterior pituitary gland. Chemical nature Polypeptide containing 8- aminoacids. Actions of Oxytocin 1. Effects on the uterus: It stimulates contraction of the smooth muscles of the pregnant uterus. It is released in large quantities just prior to delivery. 2. Effects on milk ejection: It causes increase milk ejection in lactating breasts. Stimulus for milk ejection: i) Sucking of nipples of breasts by a baby ii) Handling of breasts by a baby, iii) Crying of a baby for feeding, iv) Sight or sound of a baby. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 42 3. Effects on fertilization: Oxytocin is also released during coitus by a nervous reflex. It causes uterine contraction and has a sucking effect on seminal fluid. It accelerates transport of the seminal fluid towards the fallopian tubes, favoring fertilization. 4. Effects on blood vessels: In large doses oxytocin causes vasodilatations and decreases blood pressure. 5. Effects on pituitary gland: i) It causes prolactin secretion. ii) It inhibits ADH secretion. Clinical indications for use of oxytocin: i) Inducing labor. ii) Treatment of uterine haemorrhage Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 43 INSULIN Introduction Insulin is a small protein which acts to lower the blood glucose level. This hormone is secreted by beta cells of the islets of Langerhans of the pancreas. Chemical Nature Insulin is small soluble protein containing 51 aminoacids. Effects of insulin 1. On carbohydrate metabolism: a) It increases the entry of glucose into cells by stimulating the process of facilitated diffusion, especially in muscles, adipose tissue, the heart, smooth muscles, of the uterus by activating glucokinase. But on the other hand, insulin does not facilitate glucose entry into the brain and RBCs. b) It increases utilization of glucose for energy. c) It increases glycogen storage in cells. d) It increases the conversion of glucose into fat to be stored in adipose tissues. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 44 2. On fat metabolism: a) Forms fatty acids from excess liver glucose by activating acetyle-s- CoA carboxylase. b) Fatty acids are utilized from triglycerides which are stored in adipose tissues. c) It inhibits hydrolysis of triglycerides in fat cells by inhibiting hormone sensitive lipase. 3. On protein metabolism: a) It causes active transport of amino acids into cells. b) It promotes translation of mRNA in ribosomes to form new proteins. c) It promotes transcription of DN A in I nucleus to form mRNA. d) It inhibits protein catabolism. e) It inhibits gluconeogenesis from amino acids. 4. On growth: a) Insulin is essential for growth, as it increases protein formation. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 45 Testosterone Introduction This is the principle hormone of the testes which consists of 19 carbon atoms. Nature : Steroid in nature. Actions of testosterone 1. Effect on the male reproductive system a) During intrauterine life testosterone is secreted by the genital ridge. Later on it is secreted by the placenta. At this stage it causes the development of male sex organs including the penis, scrotum prostate, seminal vesicle, and male genital duct. This hormone also causes descent of the testes (during last 2months of gestation) and suppresses the formation of female genital organs. b) In adults testosterone is secreted by the Leydig cells of the testes. This hormone causes the enlargement of the male sexual organs. It acts on different male sex organs, increasing spermatogenesis and maintaining the motility and fertilizing power of sperm. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 46 2. Effects on secondary sex characteristics Introduction These characteristics make their appearance under the influence of sex hormones at puberty. The effects of testosterone on secondary sex characteristics are: a. Body hair: Increased growth of hairs on the face (beard and moustaches), chest, Axilla, and pubis (male pattern is convex while the female pattern is concave). b. Baldness: Decreased growth of hairs on top of the head. c) Voice: Testosterone causes hypertrophy of the laryngeal mucosa and enlargement of the larynx. It also increases the length and thickness of the vocal cords, the voice becomes deeper. d) Skin: Testosterone causes thickness of the skin, roughness of the subcutaneous tissue, deposition of melanin in skin, and also increase sebaceous gland secretion (may result in acne during puberty). e) Body changes: Testosterone causes broadening of the shoulders and hypertrophy of muscles in males. It also decreases subcutaneous fat. This is why males have less subcutaneous fatty tissues as compared to females. f) Behavioral changes: Testosterone is also responsible for aggressive moods, active attitudes, and interest in the opposite sex. 3. Effect on protein metabolism : a) It increases protein synthesis and build up the musculature. b) Causes positive N² balance. c) Decreases blood urea levels. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 47 4. Effect on CNS Increases the libido by directly acting on CNS. 5. Effect on bone a) Increases thickness of bones. b) Increases total quantity of bone matrices. c) Increases the deposition of calcium salts in bones. d) Narrows the length of the male pelvis outlet. e) Increases the length of the male pelvis and makes it funnel shaped. f) Increases the strength of the pelvis and makes it strong. 6. Effect on body length If testosterone is secreted in excessive amounts it decreases the length of the body due to the early fusion of the epiphyses. 7. Effect on BMR It increases the BMR (12-16%) due to increased protein formation. 8. Effect on RBCs Testosterone increases the number of RBCs (15- 20%). However, this difference may be due to the increased metabolic rate following testosterone administration rather than to a direct effect of testosterone on RBC production. 9. Effect on electrolyte and water balance Testosterone can increase the reabsorption of Na+ and water in the distal tubules of the kidneys. This effect of testosterone is of a minor degree. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 48 Estrogen Introduction Estrogen is a female sex hormone. Nature An 18-carbon steroid. Structure Types: The naturally occurring estrogen is of three types: i. 17- β - estradiol ii. Estrone iii. Estriol Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 49 Actions of estrogens A. Effects on reproductive system: 1. Effects on the vagina a) Increases the size of the vagina b) Causes enlargement of the musculature of the walls of the vagina. c) Changes the simple cuboidal epithelium to stratified epithelium, which is more resistant to trauma and infection. d) Increases the deposition of glycogen. e) The vaginal pH becomes more acidic due to conversion of glycogen into lactic acid by the bacteria. 2. Effects on external genitalia: a) Increases the size of the clitoris and labia minora. b) Increases the deposition of fat on the mons pubis and labia majora. 3. Effects on cervix: a) Causes slight enlargement of cervix. b) Epithelium becomes stratified. c) Increases the alkaline secretion of the cervix to neutralize the acidic pH of the vagina. 4. Effects on the uterus: a) Increases the size of the uterus. b) Changes the cuboidai epithelium into columnar epithelium. c) Causes growth of the uterine glands. d) Increases vascularity. e) Increases glycogen contents. f) Increases the sensibility of myometrium to oxytocin. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 50 5. Effects on the fallopian tubes: a) Causes the proliferation of glandular tissue. b) Increases the number and activity of ciliated epithelial cells. c) Helps in fertilization by causing peristaltic contraction. 6. Effects on ovaries: Estrogen inhibits LH and FSH secretion by a negative feed back mechanism, decreasing the ovarian function. It is used as an oral contraceptive. B. Effects on secondary sexual characteristics: 1) Effects on breast: a) Promotes the development of the tubular duct system. b) Synergistic with progesterone in stimulating the growth of the lobuloalveolar portion of the glands. Increases the deposition of fat. C) c)Responsible for their smooth appearance. 2) Effects on the skin: Increases vascularity of the skin. Causes softness and smoothness of the skin (This is why estrogen is used in creams, soaps, and oils for cosmetic- purposes) 3) Effects on the voice: The larynx of a female retains its prepubertal so size the voice remains high pitched. 4) Effects on the skeleton: a) Causes broadness of the pelvis. b) Increases the osteoblastic activity. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 51 C) Other effects: 1. Effects on protein metabolism: Increases the synthesis and deposition of proteins. Positive N2 balance. 2. Effects on fat metabolism: a) Increases the synthesis of fat.ss b) Increases the deposition of fat in subcutaneous tissue, especially the breasts, medial side of the thigh, and buttocks. 3. Effect-, on water and electrolytes: It increases the retention of Na+, Of, and water, increasing the E.C.F. 4. Effects on the menstrual cycle: This hormone is responsible for the proliferative phase of the menstrual cycle. 5. Effects on blood/cholesterol: a) Decreases blood cholesterol levels (this is why females have a low risk of hear disease). b) Raises fibrinogen levels. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 52 Progesterone Introduction: Progesterone is a female sex hormone. Nature: Steroid. Actions of progesterone: 1. Effects on uterus: a) Promotes secretory changes in the uterine endometnum during the secretory phase of the menstrual cycle. b) It prepares the uterus for implantation of the fertilised ovum. c) Decreases the excitability and snsitivitv to oxytocin. d) Decreases the frequency of uterine contractions, lengthening the period ot pregnancy (prevents expulsion of the implanted ovum). 2. Effects on Fallopian tubes: a) Promotes secretory changes in the mucosu lining of the fallopian tubes for the nutritional needs of the fertilized ovuir. b) Increases peristaltic movements from the ovary to the uterus, aiding fertilizatior. 3. Effects on cervix: a) Causes relaxation of the cervix b) Relaxin may act only in the presence of progesterone. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 53 4. Effects on vagina: a) Increases cellular proliferation b) Increases mucous secretion. 5. Effects on breast: a) Stimulates the development of tubules ancalveoli of the mammary glands b) Causes the alveolar cells to proliferate, enlarge, and become secretory 6.Effects on ovulation: Inhibits ovulation by inhibiting the release of LH and FSH. During pregnancy ovulation is inhibited by luteal and placental progesterone. 7. Effects on protein metabolism: Mobilzes proteins during pregnancy for the use of the fetus. 8. Effects on electrolyte balance: Large doses of progesterone produce natriuresi (excretion of abnormal amounts of Na" in urine). This probably occurs by blocking the action of aldosterone on the kidneys 9. Effects on skin: a) Increases the secretion of sebum on the skin and makes the hair of the scalp more oily. b) Responsible for premenstrual.icne and hair changes during pregnancv. 10. Effects on body temperature: After 24 hours of ovulation the body temperature increases due to the secretion of progesterone from the corpus luteum. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 54 ENZYMES Enzymes The enzymes can be defined as ―These are the catalysts of biological system that are produced by the living cell which are capable of catalyzing the biological reaction between certain reactants to yield specific product‖ OR The enzymes are the organic catalysts produced by the living organisms that’s why called as Biological Catalysts. Catalysts Catalyst is a chemical which is used to boost up chemical reaction but it is not utilized itself in the chemical reaction. Substrates These are the molecules on which enzymes can act. PROPERTIES OF ENZYMES  Catalytic Property Small amount of enzymes can catalyzed the large amount of substrate in a Biological reaction. Example Sucrase enzyme in its small amount easily catalyzed the hydrolytic reaction of the sucrose. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 55  Solubility Enzymes are mostly soluble in water and dilute alcohol solution. The Enzymes can precipitate in the following solvents. o Concentrated Alcohol o Ammonium Sulphate o Tricholro Acetic Acid.  Enzymatic Property The velocity of the enzymatic reaction increases as the concentration of the substrates increases up to certain maximum. But after certain period of time it decreases.  pH Acids: Acids deactivate those enzymes that act at alkaline PH e.g. Trypsin act at alkaline PH 8.57. At acidic PH it will destroy. Trypsin is an enzyme that secreted by Pancreas and very important for proper digestion of food. Bases: Bases deactivate the enzymes that act at acidic pH e.g. pepsin act at acidic PH 1-2. At alkaline PH, it will destroy. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 56  Temperature Optimum temperature is 96 F-to-99F. The optimum temperature for enzymatic activity is regard between 35 c - to - 40 c. 1. At 0 °c ----------------- Inactive 2. 10° c-to-20° c ----------------- Very little active 3. 35° c-to-40° c ------------------ Maximum active 4. 50° c ------------------- Inactive 5. 60° c -------------------- Destroy 6. In solid Condition it may be stable up to 100 ° c. The mechanism of enzyme reactions Following are the stage in a typical enzyme _catalyzed reaction. 1. Formation of enzyme _substrate (ES) complex The three dimensional structure of enzymes [E] permits them to recognize their substrates [S] in a specific manner and to form an enzyme _substrate complex, i.e. enzyme substrate → enzyme _ substrate complex or E+ S → ES. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 57 Active site Definition: The binding takes place between the substrate molecules and a place over the enzyme called the substrate site or active site. or The catalytic site can be considered to the function as cleft that can trap the substrate for which it has a high affinity and great specificity. 2. Conversion of the substrate(s) to the product (p) forming EP. ES → EP 3. Release of the product from the enzyme. EP → E+P The sequence enzyme freed from the product can now on another molecule of the substrate and so on and on. General reaction E +S → ES → EP → E+P Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 58 (Enzyme Substrate Complex) Chemical nature of enzyme With a few exceptions (certain) RNA molecules called ribozymes) Enzymes are either pure proteins or contain proteins as essential components and in addition require small non_protein molecules and metal ions which are also essential for their activity. In the latter case the protein component is called apoenzyme, while the non_ proteins Components is either a prosthetic group, a cofactor or coenzyme. The apoenzyme and the non_proteins component is either a prosthetic group, a cofactor or coenzyme. Holo Enzyme The apo enzyme and the non_ protein part together constitute the whole or complete enzyme termed holo enzyme. Non_ protein components needed for enzymatic activity. These include derivatives of B vitamins and metallic ions. Cofactors These are inorganic ions e.g. Cu+2 (cytochrome oxidase), Fe+2 or Fe+3 (cytochrome oxidase) Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 59 Coenzymes These are either organic or metallo _ organic molecules. Prosthetic group Those cofactors and coenzymes that are very tightly bound with the enzyme protein are designated as prosthetic groups. Classification of enzymes Enzymes have been named in many different ways. In many cases their names end in ht suffix as which is preceded by the name of its substrates, e.g. sucrase, lipase, urease, etc. in other cases their names describe the action of an enzymes, e.g. transmethylase, oxidase, in still other cases their names are trivial and don not at all point out their substrate or pancreatic lipase, other indicate some distinctive features of its action e.g. serine protease. According to the enzyme commission (E.C) system, there are six main classes of enzymes and as mentioned above each one of these in further subdivided into subclasses and sub-classes. The main classes are the divided are the following. i. Oxidoreductases. ii. Transferases. iii. Hydrolases. iv. Lyases. v. Isomerases. vi. Ligases. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 60 Oxidoreductases These enzymes, also called redox enzymes, catalyze oxidation – reduction reaction by transferring H atoms or hydride [H-] ions. This group is further divided into four subgroups, i.e. oxidases, dehydrogenases, hydroperoxidases and oxygenases. 1. Oxidases H2O + O2 → H2O2 H2O + O2 → H2O2 Hypoxanthine → Xanthine → Uric Acid 2. Dehydrogenases Pyruvic → lactic acid 3. Hydroperoxidases 4. Oxygenases Transferases Definition These enzymes bring about a transfer of functional group such as phosphate, amino, acyl, methyl, from one molecule to an other molecule. TYPES. 1. Transaminases 2. Phosphotransferases (Kinases) 3. Transmethylases 4. Transpeptidases 5. Transacylases Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 61 Hydrolases Definition These enzyme catalyze hydrolysis (added water is instant decomposed & functional group of substrate transferred to water) Subgroups 1. Protease 2. Carbohydrases 3. Lipid hydrolyzing enzymes 4. Deaminases 5. Deamidases Lyases Definition These enzymes catalyze the addition of NH3, H2O OR CO2 to double bonds or removal of these groups leaving behind double bonds. fumarase Fumaric acid +H2O ↔ Malic acid Isomerases Definition These enzyme catalyze the structural change in a molecule by the transfer of group in it & formation of isomeric form of subsrate. e.g Glucose 6-phosphate → fructose 6-phosphate (The enzyme is phosphohehexose isomerase) Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 62 Ligases Definition These enzymes catalyze condensation reaction joining two molecules by forming C-O,C-S,C-N, & C-C bonds along with energy releasing hydrolysis or cleavage of high energy phosphate , e.g ATP, GTP.etc Acetyle-coA → Molonyle-coA (Acetyl-CoA carboxylase) Factors affecting the enzyme Activity 1. Enzyme concentration The rate of reaction is directly proportional to the concentration of enzyme Enzyme concentration in the body may fall or rise due to changes in the rate of its synthesis and /or degradation which are brought about many factors including hormones and metabolites. 2. Substrate concentration The rate of reaction is directly proportional to the concentration of substrate upto the limit. 3. Effect of temperature The rate of reaction increases with increase in temperature over limited range of temperatue and on reaching a certain high temperature the enzyme activity starts decreasing Usually the enzyme reaction in man occur best at or round 37◦C which is the average normal body temperature. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 63 Optimum Temperature The temperature at which an enzyme reaction occurs fastest is called its optimum temperature. Some plant enzymes act best at temperature around 60◦C e.g. The enzyme DNA polymerase isolated from a bacterium named The rum aquaticus that grows in hot water springs is stable even at 90◦C. 4. Effect of pH Optimum PH Optimum PH is at which enzyme catalyzes the reaction at maximum rate. e.g Optimum PH of salivary amylase is 6.4 to 6.9 and that of trypsin is 8.0 to 9.0. Extreme changes in pH may actually denature the enzyme. 5. Presence of cofactors, coenzymes and prosthetic groups are also essential for enzymatic activity Presence of inhibitors Inhibitors Certain substances inhibit the enzyme activity called enzyme inhibitor Types: 1. Reversible inhibition 2. Irreversible inhibition Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 64 Functions of enzymes Enzyme plays a vital role in our daily life. They perform following important functions, 1. Decrease in activation Energy They decrease activation energy. Most enzymes catalyzed reaction are highly efficient Proceeding from 10³ to 108 times faster than un catalyzed reaction. H2O2 → H2+O2 ∆H=18000cal per mole If the reaction is catalyzed by enzyme then Enzyme H2O2 → H2+O2 ∆H=2000cal per mole 2. Digestion They play important role in digestion for the conversion of large complex & non diffusible molecules into smaller, simple and diffusible molecules e.g. Amylase, Trypsin, lipase etc.3. Cheese Making Enzymes are also used in the manufacturing of cheese e.g Chemosin is obtained from fungus & is used in cheese making Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 65 4. Sweetner Some enzymes are used as sweetener For example Glucosidase glucosidase Sucrose → glucose+fructose Glucose is 70٪ sweeter while fructose is 60٪ sweeter than sucrose. 5. As detergent Carbohydrate & protein breaking enzymes are heat stabilizer & are used as detergent e.g proteases 6. As drugs some enzymes are used as drugs if there is any disturbance in the digestive system, for example if there is no formation of amylase,pepsin,trypsin or lipase in the stomach or intestine these are obtained from vegetables & other resources. 7.For cancer treatment Some enzymes are used for cancer treatment for example L.asparginase Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 66 8.Curing of diseases Enzymes are also play important role in curing of diseases such as rickets & jaundice etc For heart problem lactate dehydrogenase & for liver problem certain kinases are used. 9. Blood clotting Enzymes also cause blood clotting by protein thrombin. 10. Alcoholic Beverages Amylase is used in manufacturing of alcoholic beverages i.e bear in breaking of barley by fermentation process. 11. Meat tenderizing Some enzymes like Trypsin pepsin and Papain etc s meat tenderizing to facilitate the process of digestion Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 67 CHAPTER 3 VITAMINS Definition: A vitamin is defined as naturally occurring essential organic constituents of the diet, which in minute amount aids in maintaining the normal metabolic activities of the tissues. General Properties of Vitamins: All are complex organic substances. Their molecular weight is low. Essential vitamins for one species may not be essential for another. Some vitamins are synthesized in the body. Vitamins are not destroyed in the digestive processes and are absorbed as such. The daily requirement for any vitamin is increased during growth, pregnancy and lactation. Are not act as antigenic. Classification of vitamins Fat Soluble Vitamins  Vitamin A  Vitamin D  Vitamin E  Vitamin K Water Soluble Vitamins:  Vitamin - C.  Vitamin - B Complex These are further divided, on the basis of heat stability. Thermo labile Vitamins (Affected by heat)  Thiamine (Vitamin - B1)  Antithetic Acid (Vitamin - B3) Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 68 Thermo stable Vitamins (Unaffected by heat)  Riboflavin (Vitamin - B2)  Pyridoxine (Vitamin - B6)  Niacin / Niacinamide  Biotin  Folic Acid  Cobalamin (Vitamin - B12)  Choline  Inositol  Para-amino-benzoic acid (PABA)  Lopoic Acid Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 69 Vitamin — A (Retinol) Vitamin A is a fat soluble vitamin; it is actively involved in the maintenance of normal visual process of eye. It is discovered by MC Collumin in 1915. Synonyms  Retinol.  Retinal.  Retinoic Acid. Chemical Structure Chemistry 1) The precursor or/provitamin "A" is the carotenoid pigment of certain plant know chemically as carotene. 2) Carotene is a hydrocarbon. 3) Vitamin A is quite heat stable but it is destroyed at high temperatures in the presence of O2 and air. 4) Vitamin A is a complex alcohol, found in following two forms Vitamin – A1 Vitamin – A2 The relationship between Retinol, Retinal, and Retinoic acid is as follows: Oxidation Oxidation Retinol → Retinal → Retinoic acid ← Reduction Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 70 Source 1.Retinoid Animal origin Retinol Retinal Retinoic Acid  Occur as such in nature in Animal kingdom.Liver oils of certain species of fish e.g halibut, shark and Cod. Also occur in the livers of other animals, egg yolk, butter, cheese, whole milk, kidney and muscles. Carotenoids (provitamin A) Plant origin Carotene Carotene(most efficient) Carotene  Which are yellow-red pigments, found specially in carrots, yellow corn, sweet potato, turnip, peaches and spinach.  No vitamin A activity but these are converted to vitamin A.  Poor sources of Vitamin A (Not absorbed completely and their conversion is not 100%)  Vitamin A not occur in vegetable oils. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 71 Physiological Functions of Vitamin A Eyes Vitamin a is actively involved in the maintenanace of normal visual process of eye. Retinal occurs in the retina. Vitamin A is a component of visual pigments of rod and cone cells.It combines with protein opsin to form rhodopsin which is essential for rod vision in dim light. Vitamin _ A participates both in dark/light vision as well as in colour vision Reproduction Retinol and Retinal forms of vitamin A are concerned with the normal Reproduction. Male they facilitate the process of spermatogenesis. Female they prevent fatal resorption. Epithelial tissues Vitamin-A, is appeared to be the essential factor for maintenance of normal healthy epithelial surfaces throughout the body. Essential for the formation of glycolipids and glycoproteins including those in goblet cells which secretes mucous. Antioxidant role of B carotenes These trap organic peroxide free radicals within its structure at low 02 concentration as compared to Vitamin E (acts at high 02 concentration). Bones and teeth It is essential for the normal growth and Development of bones and teeth. In some way it is construction of bones and teeth and also rates the process of mineralization. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 72 Carbohydrate metabolism Various experiments on animals have d that vitamin - A is engaged in conversion e sugar into glycogen. Enhancement of immune system Prevention of Infections Vitamin A enhances the activity of immune system. Vitamin A deficient children are susceptible to complications of measles. Vitamin keeping body surfaces/lining healthy, said as "And - infective Vitamin. Differentiation of immune system cells Mild deficiency leads to increased susceptibility to infectious diseases. Gene Expression Vitamin A binds to transcription regulatory protein that controls gene expression. Psoriasis and Acne treatment Promote healthy skin and helps to regulate the skins process of shedding dead cells and fight with bacteria. Retinoic acid preparations are commonly employed. Miscellaneous functions  Involved in mucopolysaccharide synthesis.  Involved in biosynthesis of gluco-corticoids.  Involved in protein Synthesis.  Involved in nucleic acid metabolism. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 73 Clinical features associated with deficiency of Vitamin A 1. Eyes Serious problem of the vision and eyes are found in various degrees of deficiencies of vitamin ―A‖ a. Nyctalopia Night blindness due to disturbance in visual cycle. b. Xerophthalmia Dry cornea, and mucous membranes of eye Atrophy of corneal epithelial cells Absence of tears Irritation to blinking c. Keratomalacia Keratinization and degeneration of cornea -Defective vision. Dryness, Thickness and Change in normal epithelium of cornea and conjunctiva 2. Epithelial tissues Various epithelial linings of the body are affected, they become dry, Keratinized. Nasal passage, respiratory tract, oral cavity and uro-genital tract are usually affected. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 74 3. Skin Skin become dry, scaly and thick keratinized. 1. Acne 2 Toad Skin. (irregular skin) 1) Follicular hyperkeratosis (Excessive development of keratin in hair follicles) 2) Psoriasis 4. Reproduction Male:  Atrophy of germinal epithelium of testis.  Digospermia. (Low sperm count) Female: 1) Disturbance in menstrual cycle. 5. Miscellaneous 2) Increased chances of stone formation in urinary tract 3) Increased chances of infections, especially in oral cavity, nasal sinuses, and respiratory passage, 4) Generalized growth failure, 5) Delayed Dentition, 6) Malformation of teeth and bones. Toxicity of Vitamin A (Hypervitaminois A) Acute: Headache, nausea and vomiting. Chronic: Dry skin, cracking of lips, bone pain, fragility, brittle nails, hair Loss, gingivitis, hepatomegaly, ascites and portal hypertension. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 75 Vitamin D Vitamin D is a fat soluble vitamin. Its deficiency may cause rickets in children and osteomalacia in adults. Synonyms  Calciferol,  Ergosterol.  Anti-ricketic Vitamin. Chemical Structure Vit. D3 Vit. D2 Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 76 Chemistry These are sterols, which are precursor of Vitamin D. There are about 10 compounds of Vitamin D and are named as Dl, D2, D3, D4, D5, D6, D7, D8, D9 and D10, out of these only 2 have anti-ricketic property e.g ergosterol and calciferol. Ergosterol (Provitamin D2) 7-dehydrocholestrol (Provitamin D3) UV irradiation UV irradiation Ergocalciferol (Vitamin D2) Cholecalciferol (Vitamin D3) Vegetable origin Animal origin First isolated from ergot Human epidermis D2 and D3 have same physiological actions in man. Source Vitamin D is not well distributed in nature, Cod and other fish liver oils are best sources, the few rich sources are liver of the animals which feed fish, eggs, butter, fortified milk. D3 content of milk depends on exposure to sunlight. Vitamin - D formed in the skin of human beings by ultraviolet- rays. Activation of Vitamin – D Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 77 Vitamin D is not active as such. Cholecalciferol Endoplasmic reticulum of liver cells 25-hydroxycholecalcifero (calcidiol) Kidney 1,25 dihydroxycholecalciferol (calcitriol) Factors regulating active Vitamin D3 formation Stimulated by:  Parathyroid hormone(PTH)  Hypocalcemia  Hypophosphatemia  Estrogen, Progesterone Suppressed by:  High intake of Vitamin D  Calcitriol  Increase levels of plasma calcium and inorganic phosphate Functions of Vitamin – D Absorption of calcium in gut Vitamin D promotes the Ca++ absorption from the intestine by: Increase the formation of Ca++ binding proteins in the intestine. Increase formation of Ca++/ H+ ATPase pump in intestinal cells. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 78 Phosphate absorption Intestinal absorption of phosphate is increased by Vitamin D. Serum Ca++ Level Vitamin D, maintains the serum Ca++ level by  Increased intestinal Ca++ absorption.  Increase the mobilization of Ca++ from old bones.  By increasing reabsorption of calcium and phosphate from renal proximal convulated tubule. Growth of bones Promote endochondral growth of long bones. Normal levels of calcium and phosphate favor bone mineralization. It ensures that Ca+ is deposited in the bones. Parathyroid activity Activity of parathyroid hormone is stimulated in Vitamin D deficiency. Hypercalcemia: Decreased the activity of parathyroid gland. Hypocalcemia: Increased the activity of parathyroid gland Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 79 Teeth Vitamin D helps in normal teeth formation, if vitamin D is lacking malformation of teeth occurs. Such as:  Cavity formation  Hypoplastic teeth  Defective enamel & dentine formation Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 80 Effect of Vitamin -D deficiency Deficiency of vitamin D may cause rickets in children and Osteomalacia in adults. Rickets It is a disease primarily due to a deficiency of dietary intake of vitamin D but an inadequate supply of calcium, phosphorus and sunlight may also play a part. The deficiency of vitamin D results in a lowered calcium level which stimulates the secretion of PTH which acts to restore the plasma calciumat the expense of bone calcium. Serum Phosphate level is decreased to 1 -2 mg% (Normal = 4-6mg %), due to parathyroid hormone activity. Rickets is also seen clinically when there is a defect in the conversion to calcitriol. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 81 Bones a. Osteoclastic activity, b. Resorption of Ca++ from bones, c. Bones become weak and fragile, d. Newly laid bone is un-calcified, e. Various skeletal deformities; - e.g.  Bow legs: Tibia bends forward.  Rickety rosary: Nodule develops at costochondral junction at wrist, ankles and knees.  Kyphosis: backward protrude spine  Lordosis: Side ward spine.  Scolosis: Front ward spine.  Craniotabes: Softness of skull bones  Harrison's sulcus: Transverse groove in either side of bones.  Pigeons chest: Sternum protrude forward  Pot belly abdomen. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 82 Teeth  Delayed teething  Malformed  Defective enamel production, which exposes teeth to decay  Ca+ : PO4 ratio is misbalanced Tetany It may occur when serum Ca++ level falls to 1 mg% (Normal = 9-10 mg %). Osteomalacia "Adult Rickets".  It mostly occurs in women who have little exposure to sunlight and are economically poor and undergone repeated pregnancies and lactation.  Bone minerals are mobilized, X-ray shows less dense and less mineralized bones.Ca mobilization is greater than Pi mobilization.  Bones are soft, weak and easy to get fracture.  Bowing of legs (bending of lower leg bones).  Looser's Zones is the characteristic radiographic feature.  Muscular weakness : patient will find difficulty in climbing stairs and getting out of chair.  Spontaneous fracture or collapse of vertebra are common.  Tetany may be manifested by "carpopedal spasm" and facial twitching. Toxicity of Vitamin – D (Hypervitaminosis D) Raised serum calcium and phosphate level Plasma cholesterol is raised Nausea, anorexia, vomiting, polyurea, polydipsia. G.I.T disturbances. Kidney stones formation. Calcification(deposition of calcium) of body soft tissues particularly arteries and kidneys. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 83 Vitamin – E Vitamin E is a fat soluble vitamin; it is most important vitamin to maintain the normal process of reproduction. The origin of the name tocopherol is from ―tocos‖ meaning childbirth and ―phero‖ meaning to bear, implying a substance which increases fertility. Synonyms a. Tocopherol. b. Anti sterility factor. c. Anti oxidant factor. Chemical Structure Chemistry/Properties  Fat soluble vitamin and stable to heat and acids.  Alpha-Tocopherol is the most abundant and active form of vitamin E.  These are all methyl derivatives of compound Tocol. Source: This vitamin occurs in the nature as light yellow oil. Animal: Egg yolk, milk (Human milk contains more than Cow's milk) liver, cheese, butter etc. Plant: Wheat germ oil, cotton seed oil, peanut oil etc. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 84 Functions of Vitamin E 1. Anti – Oxidant a. The main function of Vitamin E is free radical trapping antioxidant in cell membranes and plasma lipoproteins. Thus helps in maintaining the integrity of lipid moiety of cell membranes and organelles.e.g mitochondria. b.Vitamin E acts as antioxidant at high O2 partial pressure e.g. RBC membrane, membrane of respiratory tract and retina. 2. Act as Co-Enzyme In certain tissues it acts as co enzyme. 3. DNA synthesis It controls the rate of synthesis of DNA. 4. Muscles It is essential for the normal functions of muscles. 5. Care of RBCs Vitamin E looks after RBCs and prevents them from heamolysis (By preventing membrane damage by various oxidants). 6. Act as activator Acts as activation for enzyme system such as Cytochrome-C-reductase. Block No. 7, LDA Flats, Huma Block, Allama Iqbal Town, Lahore, 042-99260298  PUNJB PHARMACY COUNCIL, LAHORE BIOCHEMISTR 85 7. Reproduction It is necessary for normal process of reproduction. It keep the layers of the embryo healthy and is useful in prevention of habitual abortion. 8. Act as drug Used in Angina pectoris and in coronary insufficiency. Deficiency of Vitamin E The deficiency of vitamin E may cause following disorders: 1) Haemolysis: Rupture of RBC membrance due to increase lipid peroxidation. 2) Oedema: Specially in new born, 3) Muscular dystrophy 4) Reproduction failure 5) Male: Testicular dystrophy and defective spermatogenesis. 6) Female: I nfertility due to abnormalities in menstrual cycle, (resorption of fetus). Abortion: 7) Liver necrosis 8) Premature infants. Growth and Development retardation. Uses Recently vitamin E is used in following disorders: i. Nocturnal muscle cramps, ii. Intermittent claudication. iii. Fibrocystic breast disease, iv. Atherosclerosis. Toxicity Most studies have shown that, while taking loses of vitamin E, it has