L337H mutant of rat neuronal nitric oxide synthase resembles human neuronal nitric oxide synthase toward inhibitors.

A common dichotomy exists in inhibitor design: should the compounds be designed to block the enzymes of animals in the preclinical studies or to inhibit the human enzyme? We report that a single mutation of Leu-337 in rat neuronal nitric oxide synthase (nNOS) to His makes the enzyme resemble human nNOS more than rat nNOS. We expect that the approach used in this study can unite the dichotomy and speed up the process of inhibitor design and development.