The role of tetrahydrobiopterin in the regulation of neuronal nitric-oxide synthase-generated superoxide.

摘要: Abstract Tetrahydrobiopterin (H4B) is a critical element in the nitric-oxide synthase (NOS) metabolism ofl-arginine to l-citrulline and NO⋅. It has been hypothesized that absence of or under nonsaturating levels l-arginine where O2 reduction primary outcome NOS activation, H4B promotes generation H2O2 at expense O . The experiments were designed test this hypothesis. To theory, two different enzyme preparations, H4B-bound I H4B-free I, used. Initial rates NADPH turnover utilization found be considerably greater preparation than preparation. In contrast, initial from was substantially measured using Finally, by spin trapping nearly all produced , we rate production for I.