Clinical Chemistry 1 PDF Lecture Notes

[TRANS] CHAPTER 11: CHAPTER AMINO ACIDS AND PROTEINS OUTLINE METABOLISM I. Amino Acid About 20 AA are required by humans for protein II. Proteins...

[TRANS] CHAPTER 11: CHAPTER AMINO ACIDS AND PROTEINS OUTLINE METABOLISM I. Amino Acid About 20 AA are required by humans for protein II. Proteins synthesis cannot be synthesized in vivo at rapid III. Plasma Proteins enough rate to support growth; MUST BE SUPPLIED BY DIET IN THE FORM OF PROTEINS IV. Other Proteins of Clinical Significance Proteolytic enzymes: V. Total Protein Abnormalities o pepsin & trypsin VI. Methods of Analysis 1. completely digest dietary proteins into their constituent AA 2. they are rapidly absorbed from AMINO ACIDS intestine to the bloodstream and become part of the body’s pool of are building blocks of proteins AA Content & arrangement of AA in a specific protein are 3. AA are also released by catabolism determined by the sequence of bases in the gene that of the body proteins to use for encodes the protein energy or synthesis of new proteins Cellular growth, repair and maintenance are all dependent on AA ESSENTIAL AMINO ACIDS Chemical properties of amino acids in a specific Arginine – semi essential as dietary supplementation protein determine its biologic activity is required in youth BUT adults can synthesize Proteins catalyze almost all reactions in living cells, adequate amounts to meet body’s needs controlling virtually all cellular processes 1. Histidine 2. Isoleucine 3. Leucine Methionine BASIC STRUCTURE 4. Phenylalanine A single AA contains 1 Amino group (-NH2) & 1 5. Threonine Carboxyl group (-COOH) 6. Tryptophan N- terminal and C-terminal on different ends are 7. Valine bonded to an alpha-carbon forming the AA They only differ by their R groups (side chains) NONESSENTIAL AMINO ACIDS PEPTIDE BOND : Amino group of AA is linked with the Carboxyl group of another AA does not need additional dietary intake POLYPEPTIDE: Chain of AA is linked by Polypeptide they are produced from essential AA ; deficiency in ; A large polypeptide constitutes a PROTEIN the essential AA may requires supplementation of Proteins in human serum range from 100-150 AA in nonessential AA the length of their polypeptide chains 1. Alanine 2. Asparagine 3. Aspartic acid 4. Cysteine 5. Glutamic acid 6. Glutamine 7. Glycine 8. Proline 9. Serine 10. Tyrosine Proteins Facts: Provide up to 20% of the total energy required daily by the body o They are broken down to their constituent AA 1|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  o Amino group is removed by DEAMINATION Plays an important role in cell division, wound healing, or TRANSIMINATION stimulation of protein synthesis, immune fraction, and o DEAMINATION > UREA via urea cycle in the release of hormones liver Also important in the conversion of ammonia to o TRANSIMINATION > the resultant ketoacid urea enters into a common metabolic pathway with carbohydrates & fats to be converted into useable energy Histidine (His) o Glucogenic AA generate precursors of One of the basic by pH amino acids due to its glucose (pyruvate & citric acid cycle intermediates) imidazole side chain AA primarily used in synthesis of body proteins Needed to help-grow and repair body tissues (plasma, intracellular, structural proteins) Plays an important role in the manufacturing of RBC and WBC and in protecting the body from heavy Also used for the synthesis of non-protein nitrogen- metal toxicity containing compounds (purines, pyrimidines, porphyrins, creatine, histamine, thyroxine, An important source of carbon atoms in the epinephrine, coenzyme NAD) synthesis of purines for DNA and RN synthesis Examples: Isoleucine (Ile), Leucine (Leu), and Valine (Val) 1. Alanine deaminated to pyruvate 2. Arginine converted to alpha-ketoglutarate Collectively referred to as the branched-chain amino 3. Aspartic acid converted to oxaloacetate acid group 4. Ketogenic AA (leucine & lysine) degraded to acetyl- Promotes healing of muscle tissue, skin, and CoA /acetoacetic-CoA & form ketone bodies bones Isoleucine, phenylalanine, tryptophan, and threonine Help regulate blood glucose concentrations are KETOGENIC & GLUCOGENIC Maintain energy levels Isoleucine plays an important role in hemoglobin formation Leucine is necessary for optimal growth in infants Valine is used in treatments for muscle, mental, and emotional problems Valine & Leucine aid in maintaining the nitrogen balance in adults Lysine (Lys) Has a positive net charge, which makes it one of three basic, by charge, amino acids Plays an important role in the production of antibodies and lowering triglyceride levels; and in the formation of collagen, a component of cartilage and connective tissue Helps in absorption and conservation of calcium Methionine (Met) Helps to initiate translation of mRNA by being the first amino acid incorporated into the N-terminal position of all proteins ESSENTIAL AMINO ACID Source of sulfur, which is required for normal metabolism and growth Arginine (Arg) Assist in the breakdown of fats, helps to detoxify lead and other heavy metals, helps diminish muscle Complex amino acid often found in the catalytic weakness, and prevent brittle hair (active) site in protein and enzymes due to its amine- Reacts with adenosine triphosphate (ATP) in the containing side chain synthesis of many important substances, including epinephrine and choline 2|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor Phenylalanine (Phe) formed as a result of glycolysis in muscle tissue and conversion of pyruvate Classified as nonpolar amino acid plays a major role in the transfer of nitrogen from Promotes alertness and vitality peripheral tissues to the liver for immune system Elevates mood processes Decrease pain helps in reducing the buildup of toxic substances Aids in memory and learning released when muscle protein is broken down quickly Used to treat arthritis and depression to meet the energy demands of the body Uses an active transport channel to cross the blood- brain barrier Asparagine (Asn) Reacts with adenosine triphosphate (ATP) in the synthesis of many important substances, including derived from aspartic acid and ATP through epinephrine and choline transamidation Used by the brain to produce norepinephrine, a one of the principal and most abundant amino neurotransmitter that transmits signals between nerve acids involved in the transport of nitrogen required by the nervous system and plays an cells important role in the synthesis of ammonia in large quantities, interferes with the production of primary function is in the conversion of one amino serotonin, another neurotransmitter acid to another via amination or transamination part of the composition of aspartame, a common amination is a process by which an amine group is sweetener used in prepared foods as a sugar introduced into an organic molecule replacement transamination is the transfer of an amino acid to an plays a key role in the biosynthesis of other amino α-ketoacid acids deficiency in Phe will also result to deficiency of Aspartic acid (Asp) tyrosine also known as aspartate Threonine (Thr) synthesized from oxaloacetate through transamination an alcohol-containing amino acid that is an important role: precursor for several other amino important component in the formation of protein, acids collagen, elastin (a connective tissue protein), and a metabolite in the citric acid cycle and the urea cycle tooth enamel participates in the generation of glucose from important in the production of neurotransmitters nonsugar substrates, which is known as and health of the nervous system gluconeogenesis helps maintain proper protein balance in the body and aids liver function, metabolism, and assimilation Cysteine (Cys) Tryptophan (Trp) required supplement in infants, elderly,and individuals with metabolic diseases or intestinal absorption issues formed from proteins during digestion by the cysteine and cystine are two different amino acids, action of proteolytic enzymes named after cystine as it is an oxidized dimer of precursor for serotonin and melatonin, a neurohormone and powerful antioxidant cysteine a natural relaxant; it helps alleviate insomnia by potentially toxic inducing sleep, soothes anxiety, and reduces stable in the gastrointestinal tract and less toxic depression cystine is transported to cells and is reduced to two used in the treatment of migraine headaches, aids in cysteine molecules upon cell entry weight control by reducing appetite, and helps control significant antioxidant properties hyperactivity in children Glutamic Acid (Glu) NONESSENTIAL AMINO ACID AKA glutamate Alanine (Ala) synthesized from the transmination of a number of amino acids such as alanine and aspartic acid one of the simplest amino acids and is a product of forms another important amino acid, glutamine the breakdown of DNA or dipeptides, anserine and one of two amino acids that have a net negative carnosine charge by pH, very polar molecule serves as a neurotransmitter 3|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  important in the metabolism of sugars and fats plays an important role in the body's synthetic aids in the transport of potassium into spinal fluid pathways for pyrimidines, purines, creatine, and porphyrins Glutamine (Gln) Tyrosine (Tyr) most abundant amino acid in the body synthesized from glutamic acid synthesized from phenylalanine Essential in: important in overall metabolism o renal maintenance of the acid–base balance aiding in function of the adrenal glands, thyroid, and o provides fuel for a healthy digestive tract pituitary glands o acting as the basis of the building blocks for stimulates metabolism and the nervous system and synthesis of RNA and DNA acts as a mood elevator source of cellular energy and aids in immune function useful in the treatment of chronic fatigue, narcolepsy, transport of ammonia to the liver for metabolism anxiety, depression, low sex drive, allergies, and useful in the treatment of serious illnesses, injury, headaches. trauma, burns, cancer treatment–related side effects, and wound healing for postoperative patients Recently Identified Amino Acids Selenocysteine (Sec) Glycine (Gly) recognized as the 21st amino acid synthesized from serine unlike other aminoacids, it is not coded for directly in essential for synthesis of: the genetic code o nucleic acids It is encoded by a UGA codon, which is normally a o bile acids stop codon o Proteins selenium analogue of cysteine, in which a selenium o Peptides atom replaces sulfur o Purines o ATP discovered that HIV-1 encodes a functional o Porphyrins selenoprotein and patients with HIV infection have a o Hemoglobin lower-than-average blood plasma selenium level o Glutathione o Creatine Pyrrolysine (Pyl) o bile salts o Glucose o Glycogen not present in humans an inhibitory neurotransmitter in the CNS 22nd amino acid improves glycogen storage, and promotes healing used by prokaryotes and single-celled microorganisms as part of their methane-producing metabolism Proline (Pro) A lysine derivative is encoded by the UAG codon produced from glutamine precursor for hydroxyproline involved in wound healing, strengthening of joints, Aminoacidopathies tendons, and cardiac tissue tandem with vitamin C to promote healthy connective a class of inherited errors of metabolism tissues. there is an enzyme defect, inhibits the body's ability to metabolize certain amino acids. Abnormalities exist either in the activity of specific Serine (Ser) enzyme in the metabolic pathway or in the membrane Serine is synthesized from 3-phosphoglycerate, an transport system for amino acids. intermediate in glycolysis cause severe medical complications, such as brain needed for the proper metabolism of lipids and fatty damage. acids Due to the accumulation of toxic amino acids or their by-products in the blood and tissues. 4|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  Phenylketonuria (PKU) Phenylalanine one of the most well-known aminoacidopathies. its metabolites are found in both the blood and urine the first newborn screening test introduced in the early of patients with PKU 1960s. required for normal growth occurs in about 1 in 15,000 births in the United States diet is recommended, much lower amounts than a classic form of PKU is an absence of activity enzyme typical diet phenylalanine hydroxylase (PAH) High-protein foods should be avoided cause the urine, “musty” or “mousy” odor blood is collected at about 3 days of age. SAPROPROTEIN DIHYDROCHLODIRDE (Kuvan®) If diagnosed, the goal is to maintain blood first drug to help manage PKU concentration of phenylalanine between 120 and 600 Food and Drug Administration (FDA) approved μmol/L (2 and 10 mg/dL) helps reduce phenylalanine concentrations by Patients demonstrate an increase in phenylalanine increasing the activity of the PAH enzyme concentrations and a decrease in tyrosine only effective for patients that have some PAH activity concentrations. results from multiple independent mutations (>400 identified) at the PAH locus. GUTHRIE TEST Untreated women during pregnancy, have infants who a semiquantitative, bacterial inhibition assay are microcephalic and mentally retarded maternal To perform, an agar gel plate containing β-2- PKU are preventable if the mother maintains thienylalanine, a growth inhibitor, is inoculated with phenylalanine-restricted diet before conception and Bacillus subtilis throughout pregnancy. Blood is collected from the newborn sensitive enough to detect serum phenylalanine concentrations of 180 μmol/L (3 mg/dL) Phenylalanine hydroxylase (PAH) widely used throughout North America and Europe one of the core newborn screening tests since the late catalyzes the conversion of phenylalanine to tyrosine 1960s. absence of PAH activity, phenylalanine concentrations In recent years, test replaced by newer techniques, are usually greater than 1,200 μmol/L. such as HPLC and MS/MS untreated classic PKU, blood concentrations as high as 2.4 mmol/L can be found. MICROFLUOROMETRIC ASSAY Partial deficiencies = mild PKU, result in Another screening test for PKU phenylalanine concentrations between 600 to 1,200 for the direct measurement of phenylalanine in dried μmol/L. blood filter disks. Patients with phenylalanine concentrations, range this method yields quantitative results 180-600 μmol/L with no accumulation of more adaptable to automation phenylketones are non-PKU mild not affected by the presence of antibiotics. hyperphenylalaninemia. procedure based on fluorescence of a complex formed by phenylalanine, ninhydrin, and copper in the Hydroxyphenylalanemia presence of a dipeptide. deficiency in enzymes needed for regeneration and requires pretreatment of the dried blood filter disk with synthesis of tetrahydrobiopterin (BH4) trichloroacetic acid (TCA) BH4- a cofactor for enzymatic hydroxylation of phenylalanine, tyrosine, and tryptophan. MICROWAVE-ASSISTED SILYLATION BH4 deficiency - elevated blood concentrations of One rapid diagnostic procedure for neonatal PKU phenylalanine and deficient production of Positive screening results for PKU neurotransmitters from tyrosine and tryptophan. Must be differentiated from PKU so that treatment, GAS CHROMATOGRAPHY-MASS SPECTROMETRY active cofactor along with the neurotransmitter (GS/MS) precursors L-DOPA and 5-OH tryptophan can be initiated. amino acids are extracted from neonatal blood samples rapidly derived with N,O-bis(trimethylsilyl)- trifluoroacetamide under microwave irradiation derivatives are analyzed 5|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor MASS SPECTROMETRY Type 2 tyrosinemia an analytical technique that measures the mass-to- lack of the enzyme tyrosine aminotransferase charge ratio of charged particles. corneal erosion and lesions on palms, fingers, feet most commonly used to identify the composition of crystallization of tyrosine in the cells specimen by generating a mass spectrum representing the masses of the specimen's Type 3 tyrosinemia components. Lack of enzyme p-hydroxyphenylpyruvic acid dioxygenase MS/MS mental retardation the gold standard for detecting a variety of congenital TEST: Nitroso-Naphthol Test for Tyrosine diseases in newborns. COLOR: orange-red both analytes can be quantitated ratio of phenylalanine to tyrosine (Phe/Tyr) can be calculated. Melanuria have greater sensitivity allowing detection of lower The presence of dark pigment in the urine. concentrations of phenylalanine and earlier diagnosis may alternatively be caused by metabolic disease, of PKU such as porphyria. have ability to detect more than 25 different genetic Melanin: pigment responsible for the dark color of disorders with a single specimen hair, skin, and eyes this technology is rapidly replacing the multiple deficient production of melanin results in albinism procedures currently used in newborn screening increased urinary melanin darkens the urine programs when the laboratory can support MS/MS darkening appears after the urine is exposed to air testing. 5,6-dihydroxyindole: colorless precursor of melanin RESULTS IN: malignant melanoma DNA analysis ANALYSIS: indicates proliferation of melanocytes Prenatal diagnosis TEST: Homogentisic Acid Test detection of carrier status in families with PKU COLOR: black Alkaptonuria Tyrosinemia One of the six original inborn errors of metabolism The accumulation of excess tyrosine in the plasma Described by Garrod (1902) (tyrosinemia) producing urinary overflow may be due third major defect in the phenylalanine-tyrosine to several causes and is not well categorized. pathway Disorders of tyrosine metabolism may result from Alkali lover either inherited or metabolic defects. RESULTS IN: liver and cardiac disorders Newborns may aquire tyrosyluria as their livers may HISTORY: urine darkened after becoming alkaline be underdeveloped. from standing at room temperature Pathologic cases may show urisary crystals. CAUSE: failure to inherit the gene to produce the o Leucine and tyrosine enzyme homogentisic acid oxidase Urine screening test TEST: Homogentisic Acid Test / Ferric Chloride Test / o Nitroso-naphthol test Clinitest o Non-specific test capable of picking up other COLOR: black / transient deep blue / yellow subrstances - pos is orange red color. precipitate Further testing is warranted. Type 1 tyrosinemia Maple Syrup Urine Disease deficiency of the enzyme fumarylacetoacetate rare genetic disorder characterized by deficiency of hydrolase (FAH) an enzyme complex generalized renal tubular disorder Amino acids: leucine, isoleucine, and valine progressive liver failure in infants RESULTS IN: severe mental retardation, death Long term- hepatic carcinoma ODOR: resembling maple syrup Caused by IEM, IEM, inherited as an autosomal recessive trait. 6|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  Newborns with MSUD begin to exhibit clinical Symptoms: symptoms associated with failure to thrive after approximately l week. Near-sightedness TEST: 2,4-dinitrophenylhydrazine (DNPH) test Dislocation of the lens in the eye COLOR: yellow turbidity or precipitate Osteoporosis Mental retardation ISOVALERIC ACIDEMIA Treatment: Autosomal recessive disorder caused by mutation of Dietary restriction of proteins to reduce concentrations the IVD gene of methionine as well as high doses of vitamin B6 Plays an important role in the metabolism of leucine Treatment who do not respond may need 1 in 250,000 births in United States trimethylglycine and folic acid supplementation Guthrie Test used newborn screening Signs or Symptoms: HPLC and MS/MS commonly used as confirmatory Patient with gene mutation that cause (IVA) are methods asymptomatic Liquid chromatography-tandem mass Patient with IVA that are not asymptomatic, a spectrometry (LC-MS/MS) can be measured for characteristic feature of IVA is a distinctive odor of urinary total homocysteine concentration sweaty feet caused by the buildup of isovaleric acid Other Clinical Manifestation: CITRULLINEMIA Failure to thrive Class of genetic disease called ‘’urea cycle Vomiting disorder’’ Lethargy Inherited in an autosomal recessive pattern and occurs in two forms: Health Problems: Type 1 citrullinemia Mild to life threatening: seizures and coma Results of a mutation in the ASS1 gene Severe: This gene codes for synthesis of the enzyme permanent damage to the brain and nervous argininosuccinic acid synthetase (ASS) system and possible death ASS leads to an accumulation of the amino acid citrulline as well as ammonia in the blood Treatment: dure to impaired conversion of ammonia into urea for excretion Protein-restrictive diet Most common form occurring in about 1 in Oral administration of glycine and carnitine 57,000 births worldwide supplementation If IVA is suspected, the urine of newborns can be Symptoms: screened for isovaleric acid using MS/MS or chromatography Lack of appetite Failure to thrive Laboratory Results: Vomiting Lethargy Metabolic acidosis Mild-to-moderate ketonuria Seizures Hyperammonemia Coma Thrombocytopenia Severe brain damage or death may occur (if not Neutopenia treated promptly) HOMOCYSTINURIA Type 2 citrullinemia Inherited autosomal recessive disorder of amino acid metabolism Caused by a mutation in the SLC25A13 Mutations in the CBS, MTHFR, MTR, MTRR and gene MMADHC Citrin - helps transport molecules inside the 1 in 200,000 births worldwide cell that are used in the production and 7|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  breakdown of simple sugars, production of (When consistent high fluid intake does not stop the proteins and the urea cycle formation of stones, the drug penicillamine is Resulting accumulation of ammonia and prescribed) other toxic substances leads to: Penicillamine forms a more soluble complex with - Confusion cystine, because cystine itself, is insoluble. - Restlessness Percutaneous nephrolithotripsy – alternative - Memory loss surgery to remove the kidney stones. - Personality changes - Seizures - Coma Screening test: Treatment: Cyanide-nitroprusside Test Produces red-purple color with sulfhydryl High-caloric group Protein-restrictive diet False positives must be ruled out Arginine supplementation Large amount of urinary levels of three Administration of sodium benzoate and sodium amino acids with a similar structure to phenylacetate Cystine — Ornithine, Lysine, Arginine Ion exchange chromatography- Used for quantitative analysis for amino acids in urine ARGININOSUCCINIC ACIDURIA or plasma ‘’urea cycle disorder’’ that is inherited in an PROTEIN BASIC STRUCTURE autosomal recessive pattern Result of a mutation in the ASL gene There are 4 distinct levels of a protein’s structure: Primary, Secondary, Tertiary, and Quaternary 1 in 70,000 births worldwide Primary Structure: Number & types of amino acids in the Clinical Symptoms: specific amino acid sequence o Ex. HgbS (Sickle cell anemia) - Develop within the first few days of life and begin with Valine is substituted with glutamic lethargy and unwillingness to eat acid Secondary Structure: Treatment: Repeating structure stabilized by hydrogen bonds between amino acids High-caloric 3-dimensional conformation Protein-restrictive diet o Alpha helix; Beta pleated; Bend Arginine supplementation Involved in the winding of the polypeptide Administration of sodium benzoate and sodium chain phenylacetate Add new properties to a protein such as REMEMBER!! New born screening test cannot differentiate strength and flexibility. citrullinemia from argininosuccinic acidemia Tertiary Structure: Overall shape, or conformation of the protein. Folding or spatial relationship of secondary structures. CYSTINURIA o Maintains hydrophobic effects Quaternary Structure: Shape & structure resulting in the interaction Inherited autosomal recessive defect of more than one protein molecule, or protein Caused by a defect in the amino acid transport subunits. system rather than a metabolic enzyme deficiency. o Ex. Hemoglobin, LDH, CK Due to inability of the renal tubules to reabsorb Denaturation: cystine filtered by the glomerulus. When the secondary, tertiary, or quaternary Treatment: structure of a protein is disturbed, the protein may lose its functional and chemical High fluid intake minimum of 4L of water per day characteristics. Caused by heat, hydrolysis by strong acid or alkali, enzymatic action, exposure to urea or 8|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  other substances, or exposure to ultraviolet The mRNA is manufactured in the cell nucleus and light. then translocated across the nuclear membrane into the cytoplasm for TRANSLATION. Protein catabolism is controlled by glucagon & cortisol GENERAL CHEMICAL PROPERTIES Occurs at the rate of approximately 2-6 peptide bonds per second Structure of a protein directly affects its chemical Hormones responsible for synthesis: thyroxine, properties. growth hormone, insulin and testosterone Proteins contain many ionizable groups on the side chains of their amino acids as well as on their N- and Catabolism and Nitrogen Balance C-terminal ends A balance cycle of anabolism (synthesis) and Proteins can be positively and negatively charged degradation (catabolism) The relationship between ph, pka , and charge for Turn-over varies widely: intracellular proteins half-life individual amino acids can be described by the of hours or days while collagen may take years Henderson-Hasselbalch equation Normal nitrogen balance (intake = excretion) Nitrogen negative balance - catabolism > intake o Pregnant women, growing children, & adults recovering from illness Positive nitrogen balance - anabolism > catabolism o the pH of a solution increases, becoming more Tissue destruction (burns, wasting diseases, high alkaline, deprotonation of the acidic and basic groups fevers or starvation occurs; carboxyl groups are converted to carboxylate The breakdown of protein occurs in the digestive tract anions (R–COOH to R–COO– ) and ammonium and kidneys, but primarily in the liver groups are converted to amino groups (R–NH3+ to Two main routes for converting intracellular proteins R–NH2 ). to free amino acids: a lysosomal pathway and a Isoelectric point (pi)- the pH at which an amino acid or cytosolic pathway protein has no net charge TRANSAMINATIONS- central reactions that remove Net negative charge- pH is greater than the pI amino acid nitrogen from the body Net positive charge- pH is less than the pI Therefore, the pI is the point at which the number of Enzymes positively charged groups equals the number of negatively charged groups in a protein. Proteins that catalyze biochemical reactions Proteins differ in their pI values, but for most proteins Normally found intracellularly, but are released into it occurs in the pH range of 5.5 to 8. the bloodstream as a result of tissue damage Net charge on the surface of a protein- depends on Enzyme measurements an important diagnostic tool the number and type of amino acids it contains as well as the pH of its environment. Hormones The solubility of proteins in blood requires a pH in the Chemical messenger proteins that control the range of 7.35 to 7.45. action(s) of specific cells or organs Denaturation- loss of a protein’s native, or naturally Directly affect growth and development, metabolism, occurring, folded structure sexual function, reproduction, and behavior. SYNTHESIS Commonly tested hormones: insulin, testosterone, Synthesized in the live and released into the growth hormone, follicle-stimulating hormone, and circulation cortisol Immunoglobulins are synthesized in plasma cells Encoded by the gene in a specific nucleotide Transport Proteins sequence Three nucleotide sequence = one amino acid Proteins that are involved in the transport of ions, total number of possible codons is 64 small molecules, or macromolecules TRANSCRIPTION- process where double-stranded Commonly measured transport proteins: hemoglobin, DNA unfolds in the nucleus, and one strand is used albumin, ceruloplasmin, haptoglobin, and transferrin as a template for the formation of a complementary strand of mRNA 9|Page Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  ENZYMES Immunoglobulins Enzymes are proteins that catalyze biochemical Are proteins that are produced by B cells reactions. They are normally found intracellularly and (lymphocytes) in the bone marrow in bloodstream if there is tissue damage. Mediate the humoral immune response to identify and Transaminases, dehydrogenases, and phosphatases neutralize foreign antigens. are just a few examples of enzyme groups that are Clinically important immigg, igm, ige, and iga. routinely tested in the clinical laboratory to evaluate possible tissue damage. Structural Proteins Provide structure to many cells and tissues TRANSPORT PROTEINS throughout the body, such as muscle, tendons, and bone matrix. proteins are involved in the transport of ions, small Ex.:. Collagen, elastin, and keratin molecules, or macromolecules, such as hormones, vitamins, minerals, and lipids, across a biologic Storage Proteins membrane. commonly measured transport proteins are Serve as reservoirs for metal ions and amino acids so hemoglobin, albumin, ceruloplasmin, haptoglobin, and they can be stored without causing harm and released transferrin. later. Ferritin is a commonly measured protein that stores iron for later use in the manufacture of hemoglobin. IMMUNOGLOBULINS Energy Source Immunoglobulins or antibodies are proteins that are Some proteins serve as an energy source for tissues produced by B cells (lymphocytes) in the bone marrow and muscle Examples of immunoglobulins of clinical importance Creatine is one example of an energy source protein are IgG, IgM, IgE, and IgA. as it helps to supply energy to cells throughout the body, but is primarily found in muscle tissue. STRUCTURAL PROTEINS Fibrous proteins provide structure to many cells and tissues throughout the body CLASSIFICATIONS Examples are muscle, tendons, and bone matrix. Collagen, elastin, and keratin From 2003 to 2005, the Human Plasma Proteome Project directed by the Human Plasma Proteome STORAGE PROTEINS Organization (HUPO) distributed reference specimens of human serum serve as reservoirs for metal ions and amino acids so and plasma to 55 participating laboratories they can be stored without causing harm and released worldwide. later. To have comprehensive analysis and know their Ferritin is a commonly measured protein that stores physiologic, pathologic, and pharmacologic iron for later use. applications. Protocols used combinations of depletion, fractionation, mass spectrometry, and immunoassay ENERGY SOURCE methods linked via search engines and annotation Some proteins serve as an energy source for tissues groups to gene and protein databases and muscle. The findings from the collaborative project and Creatine is one example of an energy source protein from laboratory-specific ancillary projects were as it helps to supply energy to cells throughout the published in a special issue of Proteomics, “Exploring body the Human Plasma Proteome” in August 2005 Proteins are responsible for many different functions within cells so they are commonly classified by the OSMOTIC FORCE function(s) they perform. Some proteins function in the distribution of water throughout the compartments of the body. 10 | P a g e Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  When the concentration of plasma proteins is erosion. Increased mucin production occurs in many significantly decreased, the concomitant decrease in adenocarcinomas the plasma colloidal osmotic (oncotic) pressure results in increased levels of NUCLEOPROTEINS interstitial fluid and edema. proteins that are combined with nucleic acids. Chromatin is an example of a nucleoprotein as it is a complex of DNA and protein that makes up SIMPLE PROTEINS chromosomes. contain peptide chains composed of only amino acids. Simple proteins may be globular or fibrous in shape OTHER PROTEIN DATABASES The Structural Classification of Proteins (SCOP) GLOBULAR PROTEINS database was created to provide a detailed and Globular proteins function as transporters, enzymes, comprehensive description of the structural domains and messengers. Water insoluble of proteins. utilizes four levels of structural Examples of globular proteins are albumin, classification: class, fold, superfamily, and family. hemoglobin, and the immunoglobulins, IgG, IgA, and The Families of Structurally Similar Proteins IgM. (FSSP), also known as Fold classification, is based on the structure–structure alignment of CONJUGATED PROTEINS proteins and a three-dimensional comparison of provide structure to cells, such as connective tissues, protein structures in the Protein Data Bank. tendons, bone, and muscle. Alignments and classification are updated Examples of fibrous proteins include troponin and continuously by the Dali (Distance matrix collagen. ALIgnment) server. FIBROUS PROTEIN PLASMA PROTEINS consist of a protein and a nonprotein. The nonamino part of a conjugated protein is generally Albumin and Globulins referred to as the prosthetic group Test parameters: Examples are metalloproteins, glycoproteins, lipoproteins, and nucleoproteins. Total protein Albumin Globulins LIPOPROTEINS Albumin/Globulin (A/G) ratio composed of a protein and a lipid such as cholesterol or triglyceride examples of lipoproteins include high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs). GLYCOPROTEINS a composition of 10% to 40% carbohydrate Examples of glycoproteins are haptoglobin and α1 – antitrypsin MUCOPROTEIN/PROTEOGLYCAN If protein conjugate percentage of carbohydrate is greater than 40% An example of a mucoprotein is mucin, which is a lubricant that protects body surfaces from friction or 11 | P a g e Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor  Exists in the interstitial space (+30% vs intravascular amount) Transcapillary escape rate: measure capillary efflux of albumin Albumin transports: Thyroid hormones Iron Fatty acids Unconjugated bilirubin Dye quantification of albumin Decreased Albumin Malnutrition & malabsorption Liver disease Protein losing enteropathy Kidney loss Skin loss (oxfoliative dermatitis) Hypothyroidism Dilution by excess: Polydipsia Acute disease states Mutation (autosomal recessive state) Hemodilution Globulin Prealbumin (transthyretin) a. Alpha 1 b. Alpha 2 Moves before albumin in the electrophoresis c. Beta d. Gamma Transports: thyroxine & triiodothyronine, retinol (complex with retinol binding protein) Very short half-life = rapidly eliminated in our body ALPHA 1 ANTITRYPSIN Indicator of response to dietary supplementation. a glycoprotein mainly synthesized in the liver. Most important function: inhibition of Protease DECREASE IN PREALBUMIN CONCENTRATION neutrophil elastase Hepatic damage Problem in SERPINA1 gene: deficiency in alpha 1 Acute inflammation antitrypsin Tissue necrosis – indicator of malnutrition INCREASE o May lead to juvenile liver cirrhosis Normal antitrypsin activity: MM Allele Deficient antitrypsin activity: ZZ individual – most at risk of liver and lung disease INCREASE PREALBUMIN CONCENTARTION Steroids Measurement of alpha1 antitrypsin: Alcoholism Plasma electrophoresis Chronic renal failure Radial immunodiffusion Automated nephelometric assays Albumin Immunofixation Synthesized in the liver Highest concentration in plasma/serum 12 | P a g e Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor ALPHA 1 ANTITRYPSIN DEFICIENCY AND RESPIRATORY ACIDOSIS *neutrophil release elastase enzyme, alpha 1 antitrypsin blocks elastase enzyme because it destroys elastin in the alveoli ALPHA 1-Fetoprotein synthesized in the developing embryo, fetus , parenchymal cells of the liver AFP levels decrease gradually after birth, reaching adult levels by 8 to 12 months. In normal fetuses, AFP binds the hormone estradiol. It has an electrophoretic mobility between that of albumin and α1-globulin protein protects the fetus from immunologic attack by the mother. Conditions associated with an elevated AFP spina bifida, neural tube defects, abdominal wall defects, anencephaly (absence of the major portion of the brain), and general fetal distress. Low levels of maternal AFP indicate an increased risk for Down syndrome and trisomy , increased in the presence of twins and neural tube defects. screening is done between 15 and 20 weeks’ gestational age when the maternal AFP increases gradually. AFP levels are affected by: maternal weight race diabetes; Unconjugated estriol, and inhibin A) to determine a numeric risk for chromosomal abnormalities in the FETUS AFP can be fractionated by affinity electrophoresis into three isoforms—L1, L2, and L3—based on their reactivity with the lectin Lens culinaris agglutinin (LCA). 13 | P a g e Cadayona, David, Mamalangkas, Manlaunan, Mitmug, Mordeno, Nieve, Palaca, Ramos, Tuyor