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What is Nitric oxide is requires which of the following AA and explain in detail?
Ref. Guyton. 13th edition. Page. 208
Synthesis of NO
Nitric 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 (NOS)
The isoforms of NOS are neuronal NOS (or nNOS), endothelial NOS (or eNOS) and inducible NOS (or iNOS).