<prompt> Nitric oxide is requires which of the following AAArginineSerineThreonineLysine  <response>: Ref. Guyton. 13th edition. Page. 208Synthesis of NONitric oxide is produced by a group of enzymes called nitric oxide synthases.These enzymes convert arginine into citrulline, producing NO in the process.Oxygen and NADPH are necessary co-factors.There are three isoforms of nitric oxide synthase NOSThe isoforms of NOS are neuronal NOS or nNOS, endothelial NOS or eNOS and inducible NOS or iNOS. 