Figure 1.

Arginine biosynthesis. Schematic pathway of arginine biosynthesis from ornithine with the main acting molecules and possible metabolic destinations for arginine. * Although the implication of arginine in the biosynthesis of NO has been established in animals, it remains a matter of debate in plants. NAGS: N-acetylglutamate synthase; NAGK: N-acetylglutamate kinase; NAGPR: N-acetylglutamyl-phosphate reductase; NAOAT: N-acetylornithine aminotransferase; NAOGAcT: N-acetylornithine:glutamate acetyltransferase; NAOD: N-acetylornithine deacetylase; OTC: Ornithine transcarbamilase; ASSY: Argininosuccinate synthetase; ASL: Argininosuccinate lyase.