Biosynthesis of γ-Guanidinobutyric Acid from γ-Aminobutyric Acid and Arginine

THE recent discovery by Irreverre et al.1,2 of γ-guanidinobutyric acid in mammalian brain and other tissues stimulated research on its biosynthesis and physiological role. Thoai et al.3 have shown that in many invertebrates γ-guanidinobutyric acid is synthesized by the oxidation of arginine through the action of L-amino-acid oxidase. The present communication shows that in mammals it is synthesized by a transamidination reaction4 involving γ-aminobutyric acid and an amidine donor such as arginine.