ARGININE METABOLISM

BY

ASLAM MATANIA

GROUP-3

FACULTY OF MEDICINE

TSMU

WHAT IS ARGININE?

• Arginine is an α-amino acid

• In mammals, arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual.

STRUCTURE• The amino acid

side-chain of arginine consists of a 3-carbon aliphatic straight chain, the distal end of which is capped by a complex guanidinium group

METABOLISM

• The two main sites of endogenous arginine synthesis are LIVER(where arginine is both synthesis and hydrolyzed within urea cycle)and KIDNEY CORTEX where most of the synthesized L-arginine is released into blood and transported throughout body

•Cytosolic Enzyme required are-•argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL)

•It require 2 ATP which is convert into AMP

•synthesis of arginine occurs in intestinal–renal axis

• which produce citrulline from glutamine and glutamate,

• kidney, which extract citrulline from the circulation and convert it to arginine

ARGININE PATHWAY

CITRULLINE AND ARGININE CYCLE

• The enzyme nitric oxide synthase

(three isoenzymes) cleaves the

nitrogen from the guanidino group of

arginine to form NO.

• Requires NADPH, FMN, FAD, heme &

tetrahydrobiopterin(BH4)

AGMATINE

• Agmatine:

• It is a derivative of arginine produced in

the brain by decarboxylation.

• Agmatine possesses antihypertensive

properties.

Abnormalities • Except arginase other enzyme def. in urea

cycle distrubs arginine level in the body.• Hyperargininemia inborn error in arginine

metabolism due to a defect in the enzyme arginase.

• Hypoargininemia premature occurs before the burst of cortisol production that occurs late in preg. Cortisol is req for activation of arginine synthetic enzymes

• Remedy + of cortisol to infant(premature) may improve growth and survival rate