Catalase activity of oxygenase domain of rat neuronal nitric oxide synthase. Evidence for product formation from L‐arginine

[摘要]

Nitric oxide synthases (NOSs) catalyze the formation of nitric oxide from L-arginine. We purified the heme containing, tetrahydrobiopterin-free, oxygenase domain of rat neuronal nitric oxide synthase (nNOSox) overexpressed in Escherichia coli. We found catalase activity in nNOSox. This is significant because H₂O₂ may also be a product of nitric oxide synthases. We found H₂O₂ assisted product formation from N-hydroxy-L-arginine and even from L-arginine both in the presence and in absence of tetrahydrobiopterin. We propose how heme moiety of the oxygenase domain alone is sufficient to carry out both steps of the NOS catalysis.

[学科分类] 生物化学/生物物理

[关键词] Catalase;Nitric oxide synthase;Nitrite production;Tetrahydrobiopterin;NO;nitric oxide;NOS;nitric oxide synthase;H4B;(6R;6S)-2-amino-4-hydroxy-6-(l-erythro-1;2-hydroxypropyl)-5;6;7;8-tetrahydropterin;MOPS;3-(N-morpholino) propanesulfonic acid;DTT;dithiothreitol;Arg;L-arginine;nNOSox;rat neuronal nitric oxide synthase oxygenase domain;NHA;N-hydroxy-L-arginine