03 alanine metabolism

A i A id M t b liA i A id M t b liAmino Acids MetabolismAmino Acids Metabolism

Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi

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•• AlanineAlanine•• AlanineAlanine•• AlanineAlanine

•• ββ AlanineAlanine

•• AlanineAlanine

•• ββ AlanineAlanine•• ββ-- AlanineAlanine•• ββ-- AlanineAlanine


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AlanineAlanineAlanineAlanine

CH3 CH COOHNH2

• It is α-amino propionic acidStructureStructure

CH3 CH COOH

p pNutrional ValueNutrional Value

• It is non-essential amino acid Metabolic FateMetabolic Fate

• It is glucogenic amino acidMetabolic FateMetabolic Fate

g g


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AlanineAlanineAlanineAlanine

BiosynthesisBiosynthesis

1. From pyruvic acid


2. From serine 3 From cysteine3. From cysteine4. From tyrosine 5. From tryptophan6. From aspartic acid6. From aspartic acid


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AlanineAlanineBiosynthesisBiosynthesisBiosynthesisBiosynthesis

Glutamic acid α ketoglutaric

AminotransferaseAminotransferaseCH3 C COOH

OCH3 CH COOH

NH2PLP

AminotransferaseAminotransferase(ALT)(ALT)(GPT)(GPT)

Pyruvic Alanine

Glucose Serine Cysteine Tyrosine TryptophanAspartic

Glycine Phenyl alanine3 phosphoglycerate

ThreonineHydroxyproline

CholineGlycerol


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AlanineAlanine

Metabolic FateMetabolic Fate1. Incorporated in protein structure 2 F m ti f P i id2. Formation of Pyruvic acid3. Synthesis of glucosey g4. Glucose alanine cycle


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AlanineAlanine22-- Formation of pyruvic acidFormation of pyruvic acid22-- Formation of pyruvic acidFormation of pyruvic acid

A- Transamination

Glutamic acidα ketoglutaric

ONH2

AminotransferaseAminotransferase(ALT) (GPT)(ALT) (GPT)

CH3 C COOHO

CH3 CH COOHNH2 PLP

(ALT) (GPT)(ALT) (GPT)

B- Oxidative deamination

NH3H2O

ONH2

FMN FMNH2

L amino acid oxidaseL amino acid oxidase CH3 C COOHCH3 CH COOH


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AlanineAlanineAlanineAlanine33-- Glucose biosynthesisGlucose biosynthesis

Glutamic acidα ketoglutaric

Pyruvic acidAlanine

Glutamic acidg

PLP

AminotransferaseAminotransferase

GlucoseGlucose


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AlanineAlanine44 Glucose alanine cycleGlucose alanine cycle44-- Glucose alanine cycleGlucose alanine cycle

LiverLiver BloodBlood MuscleMuscle

Glucose GlucoseGlucose

LiverLiver BloodBlood MuscleMuscle

PyruvicPyruvicNADH.H+ NAD

LacticPyruvicPyruvic Lactic

GlutamicGlutamic

α Ketoglutaricα Ketoglutaric

AlanineAlanineAlanineg


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ββ AlanineAlanineStructure formulaStructure formula NHStructure formulaStructure formula

CH3 CH COOHNH2

CH2 CH2 COOHNH2

β Alanineα Alanine


β Alanineα Alanine

yy

1. From Aspartic acid p2. From pyrimidine catabolism3. From carnosine


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ββ AlanineAlanine11-- Biocynthesis from aspartic acidBiocynthesis from aspartic acid

COOHββ DecarboxylationDecarboxylation

CH CH COOHNH2

COOHCH2CH NH

CH3 CH COOH

α AlanineCO2

CHCOOH

NH2αα DecarboxylationDecarboxylation

CH2 CH2 COOHNH2

β AlanineAspartic CO2


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ββ AlanineAlanine22 Bisynthesis from pyrimidine catabolismBisynthesis from pyrimidine catabolism22--Bisynthesis from pyrimidine catabolismBisynthesis from pyrimidine catabolism

NH2 ONH

N

NO

HN

NO β urido propionic

NH2C

NHO CH2 CH2 COOHDeaminase

NH

O

Cytosine

NH

O β urido propionicNH3 H2O2H

H2OUracil

NH3

NH2

CO2

CH2 CH2 COOHβ Alanine


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ββ AlanineAlanine33 Bisynthesis from carnosineBisynthesis from carnosine33--Bisynthesis from carnosineBisynthesis from carnosine

NH

CH2 CH2 COOHNH2Carnosinase

NHCH2 CH2 CNH2

O

β AlanineH2OHN N

CH COOHCH2

+NH2

CH COOHCH2CarnosineHN N

Histidine


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ββ AlanineAlanineMetabolic FateMetabolic Fate1 E t i th t t f1. Enters in the structure of:

• pantothenic acidp• CoASH

2 Forms dipeptides with histidine:2. Forms dipeptides with histidine:• Carnosine• Anserine

3 Catabolized to acetyl CoA3. Catabolized to acetyl CoA


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Biosynthesis of carnosine and anserineBiosynthesis of carnosine and anserineyy

CH CH CNH2

Oβ Alanine

CH2 CH2 COOHNH2 NH

CH COOHCH2

CH2 CH2 C Oβ AlanineADP+PiATP

HN N

NH2

CH COOHCH2HN N+ H2O

CarnosineCH3

HN N

CH2 CH2 CNH2

O

HistidineCarnosine

NH

CH COOHCH2

2 2

N N

CH3

Ansirine


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ββ Alanyl histidine dipeptidesAlanyl histidine dipeptides

• activate myosin ATPase,

ββ yy

• enhance copper uptake.

• buffer the pH of anaerobically contracting skeletal muscle.

• Hydrolysis of carnosine is catalyzed by carnosinase Hydrolysis of carnosine is catalyzed by carnosinase.

• Carnosinase deficiency is characterized by

– Carnosinosis

C i i– Carnosinuria

– Muscle spasticity


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ββ AlanineAlanineββ Alanine catabolismAlanine catabolismββ--Alanine catabolismAlanine catabolism

NH2 O OD i iD i iCH2 CH2 COOH CH CH2 COOHO

CH CH3

O

CO2NH3B Alanine Malonic semialdehyde Acetaldehyde

DecarboxylationDecarboxylationDeaminationDeamination

OxidationOxidationOxidationOxidation

COOHCH3COOHCH2HOOCMalonic acid Acetic acid

ThiokinaseThiokinaseCoA.SH

H2O

CoA.SH

H2OThiokinaseThiokinase

CO-S.CoACH3CO-S.CoACH2HOOCMalonyl CoA Acetyl CoA

2


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y

Non Non αα amino acidsamino acids

1.1. ββ Alaninie Alaninie 2.2. ββ Aminoisobutyric acidAminoisobutyric acid33 γγ Aminobutyric acid (GABA) Aminobutyric acid (GABA) 3.3. γγ Aminobutyric acid (GABA) Aminobutyric acid (GABA) 4.4. δδ Aminolevulinic acidAminolevulinic acid


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Non protein amino acidsNon protein amino acids

1.1. ββ AlaninieAlaninie22 ββ A i i b t iA i i b t i idid2.2. ββ AminoisobutyricAminoisobutyric acidacid3.3. γγ AminobutyricAminobutyric acid (GABA) acid (GABA)

l ll l dd4.4. δδ AminolevulinicAminolevulinic acidacid5.5. αα Amino Amino ββ ketoadepicketoadepic acid acid 6.6. αα Amino Amino ββ ketobutyricketobutyric acidacid7.7. OrnithineOrnithine8.8. CitrullineCitrulline


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03 alanine metabolism

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