Arginine - Definition and Overview

Arginine is one of the 20 most common natural amino acids. It has a guanidino side chain functional group. In non-hepatic tissues, arginine can be biosynthesized by the ornithine cycle (or urea cycle). Even so, arginine is often classed as one of the 10 essential amino acids. This need, evidently, is restricted to children.

Arginine can be decarboxylated, yielding agmatine. Conversion by nitric oxide synthase to citrulline also yields the vasoactive mediator nitric oxide.