Arginine

http://briturtraining.com/supplements/arginine/

General features:

Abbreviated: Arg or R

Molecular formula: C₆H₁₄N₄O₂

pKa: 12.48

Physiological roles

Arginine's R group is largely positively charges in neutral and basic environments because of the double bond in the nitrogen lone pairs, thus making it have basic tendencies.  The positive charge allows arginine to form multiple hydrogen bonds.

Arginine plays important physiological roles in. Arginine is a direct precursor for the formation of nitric oxide, creatine phosphate, agmatine, polyamines, ornithine, and citrulline in the body 

Synthesis

Arginine is not considered an essential amino acid; it is largely synthesised in the body. However those who have low levels of arginine in their body can find it in a wide variety of food including dairy products beef, pork, oatmeal wheat germ and certain nuts

Arginine synthesis is eight steps away from L-glutamate syntheses and requires an additional glutamate and aspartate for completion

Synthesis begins with glutamate to N-Acertylglutamte (NAG) using a transacetylase

NAG is then phosphorylated (addition of a phosphate) to NAG phosphate (NAGP) using ATP and a NAG kinase

NAGP is reduced with NADH and a NAGP reductase to NAG semealdehyde

At this point the additional glutamate is used along with a N-Acetylornithine transaminase (AOAmT) to add an amine to NAG semialdehyde and create N-Ncetylornithine

Using Acetylornithinase (AOD) and water, acetate is removed and Ornithine is synthesized

A carbamoly phosphate molecule  is used with a Ornithine transcarbamylase (OTC) to form Citrulline

Aspartate and ATP is utilized using a Aspartate syntheses (ASS) to form Arginosuccinate

Finally an Arginosuccinate lyase (ASL) is used and a fumerate molecule is removed to form arginine




http://www.biochemj.org/bj/372/0279/bj3720279.htm