<prompt> Nitric oxide is synthesized from this amino acid:ArginineLysineLeucineIsoleucine  <response>: Ans. A. Arginine Nitric oxide is synthesized from L-Arginine Reaction is catalyzed from enzyme nitric oxide synthase. Function: Similar in reactive oxygen species in their function Potent microbial killer Produced by endothelial cells and by activated macrophages 