Biochemistry Lecture Notes Week 13 PDF

Biochemistry Lecture / Week 13 / Prof. Rogelda Bongat Leila Javier (2MT-N) PROTEINS NUTRITION AND VITAMINS - Animals cannot produce certain amino...

Biochemistry Lecture / Week 13 / Prof. Rogelda Bongat Leila Javier (2MT-N) PROTEINS NUTRITION AND VITAMINS - Animals cannot produce certain amino NUTRITION acids on their own (humans can only Nutrition create 10 out of the 20 basic amino - is the study of food and how it affects acids). the health and growth of the body; - The amino acids that animals cannot - also includes diet to mitigate disease risk, make internally must come from their e.g, excess or deficiency of specific diet (for example, by eating plants or nutrients and allergy microorganisms). - encompasses the scientific study of the - Proteins are absorbed as amino acids nutrients present in food, their - There are 20 basic amino acids; physiological utilization within the body, o 10 are essential amino acids and the intricate interplay between diet, because they are not produced well-being, and ailments. endogenously and must be - Additionally, nutrition delves into the ingested in food like plants or strategic employment of dietary microorganisms selections to mitigate disease risk. ▪ histidine, isoleucine, - It explores the repercussions when an leucine, lysine, individual experiences an excess or methionine, deficiency of specific nutrients and phenylalanine, threonine, dissects the mechanics of allergies. tryptophan, valine, and - Nutrients are substances our bodies use arginine to grow, reproduce and survive. o 11 are non-essential amino acids - Nutrients include proteins, since they can be produced by carbohydrates, fats, vitamins, minerals, the body endogenously fiber, and water ▪ Alanine, arginine, asparagine, aspartate, CLASSIFICATION OF FOOD cysteine, glutamine, - Categorically, food is classified into three glycine, proline, serine, overarching divisions: tyrosine, and glutamate - Extra protein can be used as source of Dietary Fiber energy for metabolism - are non-digestible polysaccharide - Ketogenic amino acids (aa) can be substances crucial for the optimal changed to fatty acids or ketoacids functioning of the digestive systems, o These aa can be degraded notably the colon directly to acetyl CoA or Energy-Yielding Nutrients acetoacetyl CoA, which are the - include carbohydrates, lipids, and precursor of ketone bodies and proteins, which serve as sources of myelin energy for bodily processes - Glucogenic amino acids (aa) can be changed into glucose Micronutrients o These aa give rise to net - are vitamins and minerals needed in production of pyruvate or TCA small amount by the body but have cycle intermediates, such as α- profound significance in fostering growth ketoglutarate, succinyl CoA, and development fumarate, and oxaloacetate, all - deficiency in these essential of which are precursor to glucose micronutrients can potentially lead to via gluconeogenesis; specific physiological disorders o all amino acids except lysine and - denoting dietary components commonly leucine are at least partly referred to as vitamins and minerals glucogenic 1  | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) Glucogenic Glucogenic and Ketogenic - Excess dietary CHO are converted to Ketogenic glycogen and triacylglycerols for storage (Amphibolic) Non- 1. Alanine 1. Tyrosine essential 2. Arginine LIPIDS 3. Asparagine - Fatty acids and TAGs serve as energy 4. Aspartate 5. Cysteine sources for various tissues in the human 6. Glutamate body 7. Glycine - Phospholipids play a critical role as 8. Proline 9. Serine fundamental components of all biological membranes Essential 1. Histidine 1. Isoleucine 1. Leucine - Excess dietary fat is stored as TAGs 2. Methionine 2. Phenylalanine 2. Lysine (triacylglycerols) in adipose tissue 3. Valine 3. Threonine 4. Tryptophan - Certain fatty acids (arachidonic, linoleic, or linolenic fatty acids) cannot be synthesized by the human body and obtained only from the diet thus dietary - If lots of fats and carbohydrates are deficiency becomes a challenge accessible, then the amino acids from o These essential fatty acids are extra dietary protein are converted to needed for the biological triacylglycerol and stored as fat. membranes and arachidonic - Protein is source of nitrogen in our diet acids serves as a precursor for and is in constant turnover. prostaglandins - Inside the body, protein is in a constant o These specific fatty acids are state of turnover, where it's broken down therefore classified as essential and rebuilt. fatty acids. - Additionally, during periods of growth, there's a higher requirement for protein FIBER synthesis. - Dietary fibers or roughage is the portion - Nitrogen balance refers to the of plant-derived food that cannot be equilibrium between the nitrogen completely broken down by digestive (protein) coming in and the nitrogen enzymes; being used in the body. - Found in wholegrain cereals, beans, o Positive nitrogen balance occurs peas, lentils and fruits and vegetables when more protein is taken in which remain unchanged as they pass than being used up through the stomach and intestines o Negative nitrogen balance - Mainly CHO, prevent constipation, means the body is not getting enhance gut health enough protein needed for - Cellulose - a polysaccharide found in maintenance and growth which plant cell walls, is essential for proper may lead to protein deficiency functioning of the colon - Soluble fibers – dissolves in water and CARBOHYDRATES forms a gel during digestion - PRIMARY ROLE: provide metabolic o feeling of fullness for long periods, energy slow down absorption of blood - Serve as vital structural components of sugar and cholesterol, promotes nucleic acids, glycolipids, and gut health and immunity, improve glycoproteins absorption of water and - Simple sugar undergoes breakdown in electrolytes and suppress tumor the glycolytic pathway, releasing energy; growth in colon complex CHO are first broken down into - Insoluble fibers – does not dissolve in simple sugar to enter glycolysis water and adds bulk to the stool, keep - Metabolism utilize a wide range of sugar bowel movements regular and prevent for production of energy but the brain constipation cells and red blood cells only use glucose as source of energy 2 | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) - Lignins - plant polymers made of Vitamin B6 Pyridoxine, Pyridoxal aromatic ring structures, absorb organic pyridoxal phosphate molecules in the digestive system, 5’- Vitamin B12 Cobalamin deoxyadenosyl- including binding to cholesterol cobalamin - Adequate fiber intake is associated with Methylcobalamin reduced risk for heart disease, Biotin-lysine hypertension, some git diseases, obesity, Vitamin B7: conjugates type 2 DM and certain cancers Biotin (biocytin) Lopoyl-lysine VITAMINS AND MINERALS Lipoic acid conjugates (lipoamide) - Vitamins are vital nutrients that come Vitamin B: Tetrahydrofolate only from diet, required in small amount Folic acid but deficiency can lead to disease or Vitamin C L-ascorbate even death o Vitamins are vital nutrients that Vitamin B1: Thiamine and thiamine the human body needs through pyrophosphate the diet because it lacks the - Thiamine is the precursor of thiamine ability to synthesize them, mainly pyrophosphate (TPP) due to the absence of necessary - TPP is a coenzyme for certain enzymes enzymes involved in carbohydrate metabolism - Classified as water-soluble and fat- - It catalyzes the synthesis or cleavage of soluble vitamins bonds to carbonyl carbons - Some vitamins function as coenzymes in metabolic process or coenzyme carriers Vitamin B2: Riboflavin for specific chemical groups, e.g., methyl - Riboflavin is a component of riboflavin or acyl groups 5’-phosphate (flavin mononucleotide, or - Coenzymes often undergo changes FMN) and flavin adenine dinucleotide during reactions but are then (FAD) regenerated back to their active forms, - The nucleotide part of the molecule do resulting in their efficient recycling and not enter into any chemistry, but is the need for small quantities important for recognition and binding to - All water-soluble vitamins (including enzymes that will use FMN or FAD as a vitamin C) serve as coenzymes or cofactor precursors of coenzymes - Flavin is derived from the word flavus (yellow) which is the color of the Water-Soluble Vitamins isoalloxazine ring which is the core Common Chemical Related structure of the different flavin molecules Name Name Cofactor(s) Vitamin B1 Thiamine Thiamine - Flavin coenzymes exist in 3 different pyrophosphate redox states and colors, reduced form Flavin adenine being colorless Vitamin B2 Riboflavin dinucleotide o Flavin molecules can play a part (FAD) in both one- and two- electron Flavin mononucleotide transfer reactions. (FMN) Vitamin B5: Pantothenic acid and coenzyme A Nicotinamide adenine - Pantothenic acid is part of coenzyme A dinucleotide (CoA) Vitamin B3: Nicotinic acid (NAD+) - Key functions of CoA Niacin Nicotinamide o Activation of acyl groups (R- adenine COX) for allocation to dinucleotide phosphate nucleophilic acceptors (NADP+) o Activation of 𝛼-hydrogen of the Vitamin B5 Pantothenic Coenzyme A acyl group for removal as a acid proton 3 | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) o Both of these roles involve the o Methyl group transfers using reactive sulfhydryl group all methylcobalamin through the formation of thioester Vitamin B3: Niacin (Nicotinic acid) and linkages with acyl groups Nicotinamide Coenzymes o The 4-phosphopantetheine part - Nicotinamide is an essential part of two of CoA is also utilized in the same important coenzymes: NAD+ and NADP+ way in acyl proteins (ACPs) - The reduced forms of these two enzymes involved in fatty acid biosynthesis are NADH and NADPH Vitamin B6: Pyridoxine and pyridoxal phosphate - The coenzymes participate in redox - Pyridoxal-5-phosphate (PLP) is the reactions via the direct transfer of biologically active form of vitamin B6, hydride ions (H-) either to or from the however, the nutritional requirements cofactor and a substrate can be met by either pyridoxine, - Enzymes that implicated in such redox pyridoxal or pyridoxol. reactions are called dehydrogenases - PLP participates in a wide variety of Vitamin B7: Biotin reactions involving amino acids, to - Functions as a mobile carrier of carboxyl include: transamination; beta- groups in various enzymatic decarboxylation; beta- and Gamma- carboxylation reactions elimination; racemization; and aldol - Forms a covalent bond with the enzyme, reactions acting as a prosthetic group by - These reactions encompass bonds to attaching to the amino group of lysine both the amino acid’s carbon alpha residue (Ca) and side chain carbons - Synthesized by intestinal bacteria (a rare - The versatility of PLP stems from its moment of contribution) capacity to form stable Schiff base - Adept at carrying the most oxidized form adducts with the alpha-amino groups of of carbon- carbon dioxide- using amino acids: bicarbonate as the carboxylating agent o In enzymes dependent on PLP, a - Carbon dioxide binds as carboxyl group Schiff base linkage forms to one of the ring nitrogens in biotin between PLP and the epsilon- - The amino acid where biotin and lysine amino group of a lysine residue at are conjugated is called biocytin residue the active site. - The lysine sidechain serves as a flexible - Rearrangement to a Schiff base with the tether for biotin, allowing the transfer of incoming amino acid substrate occurs carboxyl groups within the enzyme through a transaldiminization reaction Vitamin B9: Folic Acid Vitamin B12: Cyanocobalamin - Folates, folic acid derivatives, function as - Vitamin B12 is not produced by any both recipients and contributors of one- animal or plant but by a few species of carbon units for all carbon oxidation bacteria levels except for the most oxidized form, - Once in the food chain, animals get CO₂ vitamin B12 by consuming other animals - Three distinct oxidation states of carbon - Since plants are deficient of vitamin B12, can bind to tetrahydrofolate (THF), which herbivorous animals (and vegetarians) are: can suffer a deficiency o -2 (methanol group) - Vitamin B12 is present in the body as o 0 (formaldehyde group) coenzymes: 5’- o +2 (formate group) deoxyadenosylcobalamin (predominant - These groups attach to THF at either the form) and methylcobalamin N5 or N10 positions of the molecule - These coenzymes take part in 3 types of - THF, the active coenzyme, is produced reaction: by the reduction of folate by o Reductions of ribonucleotides to tetrahydrofolate reductase deoxyribonucleotides - The biosynthesis of homocysteine, o Intramolecular rearrangements methionine, purines, and thymine relies 4 | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) on the provision of one-carbon units from - Important for maintenance of normal THF. vision, regulation of cell growth and differentiation, and regulation of lipid Vitamin C: L-ascorbate metabolism - L-Ascorbate functions as a reducing - Transported to the eyes and oxidized by sugar, possessing a reactive ene-diol retinol dehydrogenase to trans-retinal → structure - Role in various biochemical processes: retinal isomerase converts it to 11-cis- o Hydroxylation of proline and retinal lysine residues within collagen - The aldehyde group of retinal forms a o Mobilization of iron, stimulation of Schiff base with lysin of the protein opsin the immune system, and acting to form rhodopsin (the light-sensitive as an antioxidant to scavenge pigment of vision) free radicals - Also needed for a variety of biological - nearly all animals have the ability to processes: involving fetal development synthesize vitamin C, as part of CHO and sperm development synthesis pathway - Excessive is toxic: - Unfortunately, humans have inherent o Acute: headache, stupor, and metabolic deficiency for vitamin C and blurred vision the gene for producing vit. C has o Chronic: weight loss, anorexia, N encountered deletions causing & V, and bone and joint pain frameshift mutation and frequent point o Retinoids – are teratogenic mutations - Vitamin C Deficiency → Impaired Collagen Formation: o Poor vessel support results in bleeding tendency ▪ Gums, skin, periosteum and joints o Inadequate synthesis of osteoid o Impaired wound healing - Vitamin A deficiency: o Eye changes o Cell differentiation Fat-Soluble Vitamins Vitamin A Retinol Vitamin D2 Ergocalciferol Vitamin D3 Cholecalciferol Vitamin E a-tocopherol Vitamin K Vitamin D: Ergocalciferol (D2) and Cholecalciferol (D3) - Cholecalciferol (Vit. D3) is produced Vitamin A: Retinol from 7-dehydrocholesterol of the skin in - Arises as an ester (retinyl ester), aldehyde the presence of UV light (retinal), or acidic form (retinoic acid) o 7-dehydrocholecalciferol → UV - Fat-soluble vitamin and is manufactured light → bond breakage between from isoprene building blocks carbons 9 and 10 → previtamn 5 | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) D3 → spontaneous formation of Vitamin K: Naphtoquinone Vit. D3 - Vitamin K is vital to the blood-clotting - Ergocalciferol arises from UV light’s effect process. on plant sterol, eorgosterol, including - Vitamin K is necessary for the commercially produced sources posttranslational modification to generate gamma-carboxy glutamic acid from glutamic acid. - Such altered residues can bind Ca²⁺, which is an essential part of the process in the clotting/coagulation cascade. - Gamma-carboxy glutamic acids in their structure VITAMINS, THEIR FUNCTIONS, AND DEFICIENCY SYNDROMES Water-Soluble Vitamins Water-soluble Functions Deficiency Functions Of 1,25-Dihydroxyvitamin D On Syndromes Calcium And Phosphorus Homeostasis As Dry and wet 1. stimulation of intestinal calcium Vitamin B1 pyrophosphate, beriberi, absorption in the duodenum (thiamine) is coenzyme in Wernicke decarboxylation syndrome, 2. stimulation of calcium reabsorption in the reactions Korsakoff kidney syndrome 3. interaction with PTH in the regulation of Converted to blood calcium; low, increase coenzymes mobilization of calcium from the bone flavin Ariboflavinosis, mononucleotide cheilosis, 4. mineralization of bone – stimulates Vitamin B2 and flavine stomatitis, osteoblast to synthesize the calcium – (riboflavin) adenine glossitis, binding protein osteocalcin, which is dinucleotide, dermatitis, involved in the deposition of calcium cofactors for corneal during bone development many enzymes vascularization in intermediary - Rickets: metabolism Incorporated into nicotinamide adenine Pellagra— Niacin dinucleotide “three Ds”: (Nicotinic (NAD) and NAD dementia, Acid) phosphate, dermatitis, involved in diarrhea Vitamin E: Tocopherol variety of redox - Alpha-Tocopherol is a potent reactions antioxidant; however, molecular details Cheilosis, glossitis, of its function are not clearly understood. Derivatives serve dermatitis, - Fatty acids in membranes are Vitamin B6 as coenzymes in peripheral predisposed to oxidative damage (pyridoxine) many neuropathy - Vitamin E is fat soluble and may protect intermediary membrane fatty acids from oxidation reactions Maintenance of myelinization - A deficiency of vitamin E results in red of spinal cord blood cells that are susceptible to tracts oxidative damage Megaloblastic - Retinal damage in premature infants, pernicious due to supplemental oxygen, may be Required for anemia and preventable by administering vitamin E Vitamin B12 normal folate degeneration (Cobalamine) metabolism and of DNA synthesis posterolateral 6 | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) spinal cord Cofactor in tracts hepatic Serves in many carboxylation of Bleeding oxidation- Vitamin K procoagulants – diathesis Vitamin C (L- reduction Scurvy factos II ascorbate) (redox) reactions (prothrombin), and VII, IX, and X, hydroxylation of and protein C collagen and protein S Essential for transfer an use Megaloblastic Folate of one-carbon anemia, neural Selected Trace Elements and Deficiency units in DNA tube defects Syndromes synthesis Elemen Function Basis of Clinical No t Deficiency Features Pantothenic Incorporated in nonexperimen- Rash Acid coenzyme A tal syndrome around recognized eyes, Cofactor in No clearly mouth, Biotin carboxylation defined clinical nose, and reactions syndrome anus called acroder- matitis Inadequate entero- supplement- pathica ation in artificial Anorexia diets and diarrhea Component Interference Zinc of enzymes, with absorp- Growth principally tion by retardation oxidases other in children dietary constituents Depressed mental Inborn error function Fat-soluble Vitamins of Fat-soluble Functions Deficiency metabolism Depressed Syndromes wound A component of Night blindness, healing visual pigment xerophthalmia, and blindness immune response Maintenance of Squamous Vitamin A specialized metaplasia Impaired epithelia night vision Maintenance of Vulnerability to Infertility resistance to infection, Essential infection particularly component measles of Inadequate Hypochro- Facilitates Iron hemoglobin diet mic intestinal Rickets in as well as microcytic absorption of children several ion- Chronic anemia Vitamin D calcium and containing blood loss phosphorus and Osteomalacia metallo- mineralization of in adults enzymes bone Component Inadequate Goiter and Major Iodine of thyroid supply of hypothy- Vitamin E antioxidant; Spinocerebellar hormone food and roidism scavenges free degeneration water radicals 7 | Biochemistry | Lecture | Week 13 | Leila Javier (2MT-N) Component of cytochrome Muscle c oxidase. Inadequate weakness Dopamine supplemen- 𝛽- tation in Neurologic hydroxylase, artificial diet defects Copper tyrosinase, lysyl Interference Abnormal oxidase, with collagen and absorption cross- unknown linking enzymes involved in cross-linking collagen Inadequate supply in soil Fluoride Mechanism and water Dental unknown caries Inadequate supplemen- tation Component of Myopathy Selen- glutathione Inadequate ium peroxidase amounts in Cardio- soil and myopathy Antioxidant water (Keshan with Vitamin disease) E --------------------------------END------------------------------- Based on ppt and manual (independent learning so no discussion notes) 8