Catalase activity of oxygenase domain of rat neuronal nitric oxide synthase. Evidence for product formation from L-arginine.
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 H(2)O(2) may also be a product of nitric oxide synthases. We found H(2)O(2) 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.
Adhikari
S
S
Department of Biophysics, Molecular Biology and Genetics, University of Calcutta, 92, A.P.C. Road, 700009, Calcutta, India.
Ray
S
S
Gachhui
R
R
D000818:Animals; D001120:Arginine; D002374:Catalase / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli; D006861:Hydrogen Peroxide; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000737:chemistry* / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D010105:Oxygenases / Q000737:chemistry* / Q000378:metabolism; D051381:Rats
D009419:Nerve Tissue Proteins; D001120:Arginine; D006861:Hydrogen Peroxide; D002374:Catalase; D010105:Oxygenases; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat