Nitric oxide protects nitric oxide synthase function from hydroxyl radical-induced inhibition.
The interdependent relationships among nitric oxide synthase (NOS), its coenzyme, cofactors and nitric oxide (NO(free radical) were studied using electron paramagnetic resonance spectroscopy. It was found that superoxide-dependent hydroxyl free radical (OH(free radical), derived from NOS coenzyme and cofactors, inhibits NOS activity, and that endogenous NO(free radical) generated by NOS scavenges OH(free radical) and protects NOS function. These results reveal a new role for NO(free radical) that may be important in NOS function and cellular free radical homeostasis.
Xu
K Y
KY
Department of Medicine, Division of Cardiology, The Johns Hopkins Medical Institutions, Johns Hopkins Asthma and Allergy Center, Room 1A2, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA. kxu@jhmi.edu
D003067:Coenzymes / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology; D006706:Homeostasis; D017665:Hydroxyl Radical / Q000032:analysis / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019097:Spin Trapping; D013481:Superoxides / Q000378:metabolism
D003067:Coenzymes; D016166:Free Radical Scavengers; D013481:Superoxides; D009569:Nitric Oxide; D017665:Hydroxyl Radical; D019001:Nitric Oxide Synthase