Biochemistry II Protein (Metabolism of Amino Acids) (New Edition)

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METABOLISM OF AMINO ACIDS

Lecture 1 : 

Lecture 1 Introduction Amino acid classification Some definitions: - nitrogen balance (NB) - protein requirement - biological value (BV) Digestion of protein Absorption of protein Metabolic fate of protein Metabolism of amino acids: - removal of ammonia: by deamination, transamination and transdeamination - fate of carbon skeletons of amino acid - metabolism of ammonia

Slide 3: 

*Metabolism of proteins is the metabolism of amino acids. NH2 COOH *Metabolism of amino acids is a part of the nitrogen metabolism in body. *Nitrogen enters the body in dietary protein. *Dietary proteins cannot be stored as such but used for formation of tissue proteins due to there is a continuous breakdown of endogenous tissue proteins.

Slide 4: 

N.B. Essential amino acids : Lysine, Leucine, Isoleucine, Valine, Methionine, Phenylalanine, Threonine, Tryptophan Nonessential amino acids: Alanine, glycine, aspartate , glutamate, serine, tyrosine, cysteine , proline , glutamine, aspargine N.B. Histidine & arginine are semi essential. They are essential only for infants growth, but not for old children or adults where in adults histidine requirement is obtained by intestinal flora & arginine by urea cycle. For formation of new tissue protein : all essential amino acids that can not be synthesized by organism & provided by dietary protein must be present at the same time with nonessential amino acids that can be synthesized by organism

Nitrogen Balance (NB): : 

Nitrogen Balance (NB): Nitrogen balance is a comparison between Nitrogen intake (in the form of dietary protein) and  Nitrogen loss (as undigested protein in feces , NPN as urea, ammonia, creatinine & uric acid in urine, sweat & saliva & losses by hair, nail, skin). NB is important in defining 1.overall protein metabolism of an individual 2.nutritional nitrogen requirement.

Three states are known for NB: : 

Three states are known for NB: a)Normal adult: will be in nitrogen equilibrium, Losses = Intake b)Positive Nitrogen balance: Nitrogen intake more than losses (High formation of tissue proteins) occurs in growing children, pregnancy, lactation and convulascence. C)Negative Nitrogen balance: Nitrogen losses more than intake occurs in:- (Low intake of proteins) in starvation, malnutrition, GIT diseases - (High loss of tissue proteins ) in wasting diseases like burns, hemorrhage& kidney diseases with albuminurea - (High breakdown of tissue proteins ) in D.M., Hyperthyroidism, fever, infection

Protein Requirement for humans in Healthy and Disease Conditions : 

Protein Requirement for humans in Healthy and Disease Conditions The normal daily requirement of protein for adults is 0.8 g/Kg body wt. day-1. That requirement is increased in healthy conditions: during the periods of rapid growth, pregnancy, lactation and adolescence. Protein requirement is increased in disease states: illness, major trauma and surgery. RDA for protein should be reduced in: hepatic failure and renal failure

Biological Value for Protein (BV): : 

Biological Value for Protein (BV): * BV is : a measure for the ability of dietary protein to provide the essential amino acids required for tissue protein maintenance. * Proteins of animal sources (meat, milk, eggs) have high BV because they contain all the essential amino acids. * Proteins from plant sources (wheat, corn, beans) have low BV thus combination of more than one plant protein is required (a vegetarian diet) to increase its BV.

DIGESTION OF PROTEIN : 

DIGESTION OF PROTEIN Proteins are broken down by hydrolyases (peptidases or proteases): Endopeptidases attack internal bonds and liberate large peptide fragments (pepsin, trypsin, Chymotrypsin & Elastase) Exopeptidases remove one amino acid at a time from – COOH or –NH2 terminus (aminopeptidase & carboxypeptidase) Endopeptidases are  important for initial breakdown of long polypeptides into smaller ones which then attacked by exopeptidases. Digestion of protein can be divided into: a gastric, pancreatic and intestinal phases.

I. Gastric Phase of Protein Digestion: (represents 15% of protein digestion) : 

I. Gastric Phase of Protein Digestion: (represents 15% of protein digestion) 1) Pepsin: in adult stomach , secreted as pepsinogen.It is specific for peptide bond formed by aromatic or acidic amino acids 2) Rennin: in infants for digestion of milk protein (casein).

II. Pancreatic Phase of Protein Digestion : 

II. Pancreatic Phase of Protein Digestion This phase ends with free amino acids and small peptides of 2-8 amino acid residues which account for 60% of protein digestion Small intestine Dietary protein Trypsin Trypsinogen Chymotrypsin Chymotrypsinogen Elastase Proelastase Enteropeptidase BASIC UNCHARGED ALIPHATIC BASIC

III. Intestinal Phase of protein digestion: : 

III. Intestinal Phase of protein digestion: Intestinal enzymes are: aminopeptidases (attack peptide bond next to amino terminal of polypeptide) & dipeptidases The end product is free amino acids dipeptides & tripeptides.

Slide 13: 

Absorption of Amino Acids and Di- &Tripeptides:

Absorption of Amino Acids and Di- &Tripeptides: : 

Absorption of Amino Acids and Di- &Tripeptides: *L-amino acids are actively transported across the intestinal mucosa (need carrier, Na + pump, Na+ ions, ATP). Different carrier transport systems are: a) For neutral amino acids. b ) For basic amino acids and cysteine. c) For imino acids and glycine. d) For acidic amino acids. e) For B-amino acids (B-alanine & taurine). *D-isomers transported by simple diffusion.

The transcellular movement of amino acids in an intestinal cells: : 

The transcellular movement of amino acids in an intestinal cells: blood Amino acid Amino acid Amino acid Na+ Na+ Na+ K+ K+ Lumen Cytosol Extracellular fluid (Antiport) (Symport)

Tri- & Dipeptides can actively transported faster than their individual amino acids. : 

Tri- & Dipeptides can actively transported faster than their individual amino acids. intact proteins: 1. Immunoglobulins of colostrum are absorbed by neonatal intestines through endocytosis without loss of their biological activity and thus provide passive immunity to the infants. 2. Vaccines (undigested polypeptides) in children and adults are absorbed without loss of their biological activity producing antigenic reaction and immunologic response.

METABOLIC FATES OF AMINO ACIDS: : 

METABOLIC FATES OF AMINO ACIDS: 1- Body protein biosynthesis. 2- Small peptide biosynthesis(GSH). 3-Synthesis of non-protein nitrogenous (NPN) compounds (creatine, urea, ammonia and uric acid) 4- Deamination & Transamination to synthesized a new amino acid or glucose or ketone bodies or produce energy in starvation.

Slide 18: 

Sources & fates of amino acids: Protein turnover : (results from simultaneous synthesis & breakdown of proteins molecules) Total amount of protein in body of healthy adult is constant (due to rate of protein synthesis is equal to the rate of its breakdown). Body protein 400 g per day,synthesis Body protein 400 g per day breakdown Dietary protein Synthesis non- essential a.as. GL.&Glycogen Ketone bodies Fatty acid& steroids CO2& E

Metabolism OF AMINO ACIDS: : 

Metabolism OF AMINO ACIDS: R Removal of amonia by : NH2 CH COOH - Deamination Oxidative deamination 1) glutamate dehydrogenase in mitochondria 2) amino acid oxidase in peroxisomes Direct deamination (nonoxidative) 1) dea. by dehydration (-H2O) 2) dea. by desulhydration (-H2S) - Transamination (GPT & GOT) - and transdeamination. Fate of carbon-skeletons of amino acids Metabolism of ammonia

Deamination of Amino Acids : 

Deamination of Amino Acids Oxidative Deamination: 1) Glutamate dehydrogenase , mitochondrial , potent, major deaminase It is allosterically stimulated by ADP & inhibited by ATP, GTP & NADH. Thus, high ADP (low caloric intake) increases protein degradation high ATP ( well fed-state) decreases deamination of amino acids & increases protein synthesis. -NH3 a-Keto acid Amino acid

2) Amino Acid Oxidases: : 

2) Amino Acid Oxidases: The minor pathway for deamination of amino acids. They are found in peroxisomes of liver and kidney. L-amino acid oxidases utilize FMN while D-a.a. oxidases utilize FAD.

Slide 22: 

D-amino acid oxidases are highly active than L-amino acid oxidases especially in kidney and liver due to: the function of D-amino acid oxidases is the rapid and irreversible breakdown of D-amino acids since: D- amino acids are potent inhibitors to L-amino acids oxidases

b) Non-oxidative deamination: (Direct Deamination ) : 

b) Non-oxidative deamination: (Direct Deamination ) Deamination by dehydration: Serine & Threonine

2) Deamination by desulfhydration : (cysteine) : 

2) Deamination by desulfhydration : (cysteine)

Transamination: : 

Transamination: Aminotransferases are active both in cytoplasm and mitochondria e.g.: 1. Aspartate aminotransferase (AST), Glutamate oxaloacetate transaminase (GOT), 2. Alanine aminotransferase (ALT), Glutamate pyruvate transaminase, (GPT) In all transamination reactions, a-ketoglutarate (a –KG) acts as amino group acceptor. Most, but not all amino acids undergo transamination reaction with few exceptions (lysine, threonine and imino acids) NH2 O a –KG O NH2 GLU

The role of PLP as Co-aminotransferase :PLP binds to the enzyme via schiff’s base & ionic salt bridge & helps in transfer of amino group between amino acid and keto acid (KG): : 

The role of PLP as Co-aminotransferase :PLP binds to the enzyme via schiff’s base & ionic salt bridge & helps in transfer of amino group between amino acid and keto acid (KG): New keto acid O NH2 New amino acid 2 R1 R1 R1 R2 R2

Metabolic Significance of Transamination Reactions : 

Metabolic Significance of Transamination Reactions It is an exchange of amino nitrogen between the molecules without a net loss This metabolically important because: There is no mechanism for storage of a protein or amino acids. In case of low energy (caloric shortage), the organism depends on oxidation of the ketoacids derived from transamination of amino acids. It is important for formation of the non-essential amino acids

Transdeamination: : 

Transdeamination: Due to…L-amino acid oxidases, but not glutamate dehydrogenase, can sluggish (decrease) the rate of deamination of the amino acids. So… the most important and rapid way to deamination of amino acids is first transamination with a-ketoglutarate followed by deamination of glutamate. Therefore glutamate through transdeamination serves to a funnel ammonia from all amino acids. Transamination Deamination with Glu.D.H. Amino acid a-ketoglutarate NH3 Funnel

THE FATE OF CARBON-SKELETONS OF AMINO ACIDS : 

THE FATE OF CARBON-SKELETONS OF AMINO ACIDS a) Simple degradation: (amino acid Common metabolic intermediate) Alanine Pyruvate Glutamate a-ketoglutarate Aspartate Oxaloacetate b) Complex degradation: (amino acid--- Keto acid----- complex pathway---- Common metabolic intermediate) Amino acids whose ketoacids are metabolized via more complex pathway e.g. Tyrosine, Lysine, Tryptophan c) Conversion of one amino acid into another amino acid before degradation: Phenylalanine is converted to tyrosine prior to its further degradation.

The common metabolic intermediates that arised from the degradations of amino acids are: acetyl CoA, pyruvate, one of the krebs cycle intermediates (a-ketoglutarate, succinyl CoA, fumarate& oxaloacetate) : 

The common metabolic intermediates that arised from the degradations of amino acids are: acetyl CoA, pyruvate, one of the krebs cycle intermediates (a-ketoglutarate, succinyl CoA, fumarate& oxaloacetate) Citrate cycle

Metabolism of the Common Intermediates : 

Metabolism of the Common Intermediates 1.Oxidation: all amino acids can be oxidized in TCA cycle with energy production 2.Fatty acids synthesis: some amino acids provide acetyl CoA e.g. leucine and lysine (ketogenic amino acids). 3.Gluconeogenesis: ketoacids derived from amino acids are used for synthesis of glucose (is important in starvation). Glucogenic Ketogenic Glucogenic&Ketogenic Ala, Ser, Gly, Cys, Leu , Lys Phe,Tyr,Trp,Ile,Thr Arg, His, Pro, Glu, Gln, Val, Met, Asp, Asn.

METABOLISM OF AMMONIA : 

METABOLISM OF AMMONIA Ammonia is formed in body from: From amino acids: 1.Transdeamination in liver (NOT T.A.) 2.amino acid oxidases and amino acid deaminases in liver and kidney. b) Deamination of physiological amines: by monoamine oxidase (histamine, adrenaline, dopamine and serotonine). c) Deamination of purine nucleotides: especially adenine nucleotides AMP IMP + NH3 d) Pyrimidine catabolism. e) From bacterial action in the intestine on dietary protein & on urea in the gut. NH3 is also produced by glutaminase on glutamine .

Metabolic Disposal of Ammonia : 

Metabolic Disposal of Ammonia Glutamine is storehouse of ammonia & transporter form of ammonia. In brain, glutamine is the major mechanism for removal of ammonia while in liver is urea formation. ..Circulating glutamine is removed by kidney, liver and intestine where it is deamidated by glutaminase . Glutamate c) Urea formation

Slide 34: 

.. Diet & body protein a-A . a. Glu. Biosynthesis Of purine & Pyrimidine Urine NH4+ Urine Kidney Liver Kidney This reaction is important to kidney due to kidney excretes NH4+ ion to keep extracellular Na+ ion in body and to maintain the acid-base balance. Deaminase GIT Diet & Body protein glutamine urea Purines,pyrimidines Various nitrogen-containing compounds glutaminase Bacterial urease

c) Urea Formation : 

c) Urea Formation Urea is the principal end-product of protein metabolism in humans. It is important route for detoxication of NH3. It is operated in liver, released into blood and cleared by kidney. Urea is highly soluble, nontoxic and has a high nitrogen content (46%), so …it represents about 80- 90% of the nitrogen excreted in urine per day in man Biosynthesis of urea in man is an energy- requiring process. It takes place partially in mitochondria and partially in cytoplasm.

Slide 36: 

The Urea Cycle (The Ornithine Cycle, Kreb's Henseleit Cycle): NAD MDH o H2 Glu Glu NADH2

Metabolic Significant Aspects of Urea Cycle : 

Metabolic Significant Aspects of Urea Cycle A) Energy Cost:. Energy cost of the cycle is only one ATP. B) urea cycle is related to TCA cycle: 1. CO2 2.Aspartate arises via transamination of oxaloacetate with glutamate. Thus, depletion of oxaloacetate will decrease urea formation (as in malonate poisoning). 3. Fumarate enters TCA cycle C) Sources of Nitrogen in urea :free NH3 and aspartate. N.B. glutamate is the immediate source of both NH3 (via oxidative deamination by Glu. Dehyd.) and aspartate nitrogen (through transamination of oxaloacetate by AST).

Importance of Urea Cycle : 

Importance of Urea Cycle Formation of arginine (in organisms synthesizing arginine) & formation of urea (in ureotelic organisms, man) due to presence of arginase. Liver shows much higher activity of arginase than brain or kidney for formation of urea while in brain or kidney is the synthesis of arginine. Synthesis of non-protein amino acids (ornithine and citrulline) in body.

Regulation of Urea Cycle : 

Regulation of Urea Cycle 1) Activity of individual enzymes: THE RATE LIMITING STEPS a) carbamoyl phosphate synthase-1 b)  Ornithine transcarbamyolase. c) Arginase. N-acetylglutamate is activator for carbamoyl phosphate synthase-1 It enhances its affinity for ATP. It is synthesized from acetyl CoA and glutamate. its hepatic concentration increases after intake of a protein diet, leading to an increased rate of urea synthesis. Activity of ornithine transcarbamyolase is limited by the concentration of its co-substrate "ornithine".

2) Regulation of the flux through the cycle: : 

2) Regulation of the flux through the cycle: Flux of ammonia: 1.by amino acids release from muscle (alanine, glutamine), 2. metabolism of glutamine in the intestine 3. amino acids degradation in the liver. b) Availability of ornithine. c) Availability of aspartate: since aspartate is required in equimolar amounts with ammonia, this is satisfied by of transdeamination . 3) Change in the level of Enzymes: Arginase & other urea-forming enzymes are adaptive enzymes thus a protein-rich diet will increase their biosynthesis rate & the opposite is true for low protein diet. However, in starvation, where the body is forced to use its own tissue protein as fuel, there is an increase in urea-forming enzymes.

ONE-CARBON FRAGMENT METABOLISM : 

ONE-CARBON FRAGMENT METABOLISM Human body is unable to synthesize the methyl group and obtain it from diet. The first: met = S-adenosyl methionine (methyl donner = CH3 ) involved in transmethylation reaction The second: tetrahydrofolic acid (FH4 or THF) which is a carrier of active one-carbon units (-CH3, -CH2, -CHO, -CHNH, -CH).

Slide 43: 

10 5 The one-carbon group carried by THF is attached to its N5 or N10 or to both.

Slide 44: 

These one-carbon units are interconvertible to each other. The primary sources of one-carbon units are serine, glycine, histidine, tryptophan & betaine. and their acceptors for biosynthesis a variety of biomolecules are Phosphatidylethanolamine, Guanidoacetic acid, nor-Epinephrine ,Thymine, Purine-C8 & Purine-C2 & homocysteine.

METABOLISM OF INDIVIDUAL AMINO ACIDS : 

METABOLISM OF INDIVIDUAL AMINO ACIDS Metabolism of Glycine: nonessential, glucogenic. Biosynthesis of glycine: 1 2 H2O

Slide 46: 

Degradative pathway: Hyperoxaluria  1. Reaction 2. 3 2.

Special Functions of Glycine: : 

Special Functions of Glycine: a-Protein, Hormones & enzymes. b- Heme c- Purines (C4,C5,N7) d- Creatine e- Glutathione f- Conjugating reactions:  Glycine + Cholic acid  glycocholate.  Glycine + Benzoic acid  Hippuric acid 1.Formation of Glutathione (GSH)  Dest.FR & Peroxides glycine

2. Formation of creatine (Methyl guanidoacetate) : 

2. Formation of creatine (Methyl guanidoacetate) kidney liver Guanido acetate Arginine Glycine Creatine phosphate Creatinine Nonenzymatic in muscle

Slide 49: 

Creatine Creatine phosphate CPK ATP ADP EXCESS ATP DURING EXERCISE Cr-P is the storage form of high energy phosphate in muscle Creatinine is excreted in urine & increases on kidney failure due to its filteration is decreased. Its level is constant per 24 hrs & is proportional to muscle mass in human. NON ENZYMATIC IN MUSCLE Pi+H2O CREATININE

Metabolism of Serine: nonessential & glucogenic : 

Metabolism of Serine: nonessential & glucogenic It is synthesize from glycine or intermediate of glycolysis, all enzymes are activated by testosterone in liver, kidney & prostate. o NH2

Degradative Pathways of Serine: : 

Degradative Pathways of Serine: Serine is important in synthesis of: a. Phosphoprotein b. Purines & pyrimidine c. Sphingosine d. Choline e. Cysteine Serine Glycine CO2+NH3 (major) 1. 2.

Metabolism of Sulfur-Containing amino acids (Methionine, cyteine & Cystine): : 

Metabolism of Sulfur-Containing amino acids (Methionine, cyteine & Cystine): Metabolism of methionine: (essential) 2 principal metabolic pathways: Transmethylation and transsulfuration Transmethylation Met. Cysteine (diet.pr.) NH2 +

In transmethylation there are: : 

In transmethylation there are: Methyl acceptors Methyl Compounds 1- Guanidoacetic acid Creatine 2- Norepinephrine Epinephrine 3- Ethanolamine Choline 4- Uracil Thymine SAM SAH (S-Adenosyl Homocysteine)

Slide 56: 

Homocystinuria Lack of Cystathionine synthase C-skeleton of cysteine From serine & S from methionine Methionine

Metabolism of Cysteine& Cystine:- They are interconvertable &They are not essential- can be synthesized from Met & Ser : 

Metabolism of Cysteine& Cystine:- They are interconvertable &They are not essential- can be synthesized from Met & Ser

Degredative pathway of cysteine: : 

Degredative pathway of cysteine: Pyruvate Transamination Oxidative pathway Non oxid. pathway

Biochemical functions of cysteine : 

Biochemical functions of cysteine 1- PAPS Formation: (3'-phosphoadenosine,5'-phosphosulphate)active sulphate used in formation of sulfate esters of steroids, alcohol, phenol,some lipids, proteins and mucopolysaccharides 2- Sulfur of COASH, GSH, vasopressin, insulin 3-Detoxication reaction of bromo, chloro, iodobenzene, naphthalene and anthracene & of phenol, cresol, indol and skatol that is formed by the action of intestinal bacteria on some amino a cids in large intestine with formation of ethereal sulfates which is water soluble and rapidly removed by the kidney 4- Taurine Formation ( with bile acids form taurocholate) e

Polyamines (Spermidine & Spermine) : : 

Polyamines (Spermidine & Spermine) : (1) Spermine & spermidine are growth factors, so they are important in cell proliferation and growth. (2) They are important in stabilization of cells and subcellular organelles membranes. (3)They have multiple + Ve charges and associate with polyanions such as DNA, RNAs and have been involved in stimulation of RNA and DNA biosynthesis as well as their stabilization. (4)They exert diverse effects on protein synthesis and act as inhibitors of protein kinases

Biosynthesis: : 

Biosynthesis: Arginine Met. 1,4 Diaminobutane 1,3 Diaminopropane 1,3 Diaminopropane A 1 2 3 4 A 1 2 3

Catabolism of Polyamine : 

Catabolism of Polyamine oxidase

Aromatic amino acidsa) Metabolism of Phenylalanine (glucogenic & ketogenic) : 

Aromatic amino acidsa) Metabolism of Phenylalanine (glucogenic & ketogenic) OH O O glucose Ketone body α

b) Tyrosine is a precursor of:1.DOPA (3,4 dihydroxy phenylalanine) : 

b) Tyrosine is a precursor of:1.DOPA (3,4 dihydroxy phenylalanine)

2.Thyroid hormones: Thyroxine Formation: : 

2.Thyroid hormones: Thyroxine Formation:

Thyroglobulin(Tgb) : 

Thyroglobulin(Tgb) It is the precursor of T3 and T4 It is large, iodinated, glycosylated protein. It contains 115 tyrosine residues each of which is a potential site of iodination. 70% iodide in Tgb exists in the inactive forms MIT&DIT WHILE 30% is in T3& T4 About 50 μg thyroid is secreted each day.

Biosynthesis of Thyroid hormones : 

Biosynthesis of Thyroid hormones Includes the following steps: Concentration of iodide: the uptake of I by the thyroid gland is an energy dependent process & is linked to active Na pump. Oxidation of iodide: the thyroid is the only tissue that can oxidize I to a higher valence state Iodination of tyrosine: oxidized I reacts with tyrosine residues in thyroglobulin form MIT & DIT. Coupling of iodotyrosyls: The coupling of two DIT T4 or of MIT & DIT T3

c) Tryptophan (essential,glucogenic&ketogenic)I] 3-hydroxyanthranilic acid pathway: : 

c) Tryptophan (essential,glucogenic&ketogenic)I] 3-hydroxyanthranilic acid pathway: Trp pyrrolase Inc.by Cortico. & tryptophan & Dec.by Niacin, NAD & NADP H OH 3

II] Serotonin Pathway: : 

II] Serotonin Pathway: * Neurotransmitter * Founds in mast cells& platelets. * Vasoconstrictor for B.V.& bronchioles * Transmitter in GIT to release the peptide hormones.

III] Melatonin formation pathway : 

III] Melatonin formation pathway It is the hormone of pineal body in brain of man. Formed by the acetylation and methylation of serotonin. It has effects on hypothalamic-pituitary system. It blocks the action of MSH & ACTH. It is important in regulation of gonad & adrenal functions. It has a circadian rhythm due to its formation occurs only in dark,due to high activity of N-acetyl transferase enzyme so it is a biological clock. It keeps the integrity of cells during aging due to it has an antioxidant property It enhances the body defense against infection in AIDS patients by increasing the number of immune cells. It reduces the risk of cancer&heart diseases

IV] Indol, skatol and indicant pathway: : 

IV] Indol, skatol and indicant pathway: Indol & skatol contributes to unpleasant odour of feces. Skatoxyl and indoxyl are absorbed from large intestine and conjugated with sulfate in the liver and excreted in urine as indican (K indoxyl sulfate).

Basic Amino Acids:1)   Histidine (glucogenic amino acid): : 

a)  Together with B-alanine , It forms carnosine (B-alanyl histidine) and anserine (methyl carnosine): 1. They are buffer the pH of anerobically contracting skeletal muscle 2.They activate myosin ATP-ase 3.They chelate copper and enhance Cu2+ uptake. b) Histidine is a  source of one-carbon atom. c)       Histidine Histamine Histamine is a chemical messenger that mediates allergic and inflammatory reactions, gastric acid secretion and neurotransmission in the brain. decarboxylase Basic Amino Acids:1)   Histidine (glucogenic amino acid):

(2) Arginine: (nonessential & glucogenic amino acid): : 

(2) Arginine: (nonessential & glucogenic amino acid): It participates in formation of: a)Creatine b)Polyamines C)Nitric oxide NO (Free radical gas).

3) Lysine: (essential, ketogenic) it is involved in the formation of histone, hydroxylysine & carnitine: : 

3) Lysine: (essential, ketogenic) it is involved in the formation of histone, hydroxylysine & carnitine:

Acidic Amino Acids :1.Glutamic acid : (nonessential & glucogenic amino acid). : 

Acidic Amino Acids :1.Glutamic acid : (nonessential & glucogenic amino acid). It participates in formation of: 1-  GSH. 2- Glutamine: as storage and transporter form of ammonia 3- GABA (-aminobutyric acid) neurotransmitter in brain.

2. Aspartic acid: Acidic, non essential & glucogenic : 

2. Aspartic acid: Acidic, non essential & glucogenic Arginosuccinate in urea cycle. Alanine by decarboxylation. 3. Oxalate & glucose by T.A. Amino acids as precursors of neurotransmitters 1. Arginine --------------NO 2.Tryptophan-----------Serotonin 3. Histidine--------------Histamine 4. Phenyl alanine------dopa,dopamine, NE&E 5.Glutamic acid--------GABA

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