A comparative study of neuronal and inducible nitric oxide synthases: generation of nitric oxide, superoxide, and hydrogen peroxide.
Nitric oxide synthases (NOS) independent of the isozyme, produce nitric oxide (.NO), superoxide (O2.-), and hydrogen peroxide (H2O2). Since .NO has been implicated in many physiological processes, the importance of O2.- and H2O2 in regulating cell signaling by .NO cannot be overlooked. Before addressing these questions, we investigated the production of .NO, O2.-, and H2O2 by purified NOS. NOS 1 and NOS 2 were chosen, as the flux of .NO from each isozyme supports differential biological activity. We found that the initial rate and sustained production of .NO was considerably greater for NOS 2 as compared to NOS 1. In the absence of L-arginine, however, NOS 1 generation of O2.- and H2O2 was found to be substantially greater than that measured for NOS 2. Differences between NOS 1 and NOS 2 production of .NO, O2.-, and H2O2 may define the specific physiologic function of each isozyme.
Weaver
John
J
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA.
Porasuphatana
Supatra
S
Tsai
Pei
P
Pou
Sovitj
S
Roman
Linda J
LJ
Rosen
Gerald M
GM
D006861:Hydrogen Peroxide / Q000378:metabolism*; D008956:Models, Chemical; D009249:NADP / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D052248:Nitric Oxide Synthase Type I / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D052247:Nitric Oxide Synthase Type II / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D010084:Oxidation-Reduction; D030421:Peroxynitrous Acid / Q000096:biosynthesis; D013481:Superoxides / Q000378:metabolism*
D013481:Superoxides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D009249:NADP; D006861:Hydrogen Peroxide; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II