Effect of certain metabolites & proteins- on production of superoxide radical by Nishikimi's reaction
Kiran, U.; Sudershan; Ahuja, B.S.
Indian Journal of Biochemistry and Biophysics 18(1): 84-85
1981
ISSN/ISBN: 0301-1208 PMID: 6268527 Document Number: 180763
Superoxide anion radical .O2- production (non-enzymatic) was measured colorimetrically, using NADH in phenazine methylsulfate (PMS) and nitro blue tetrazolium (NBT) system. Compounds like semicarbazide hydrochloride, oxidized glutathione and cystenium chloride inhibit production of .O2- by the system (20-90%), whereas 2,2-bipyridyl and 4,4'-bipyridyl have no effect on the reaction. Sodium cyanide and ascorbic acid stimulate .O2- production. Similarly some proteins such as catalase, cytochrome c and xanthine oxidase show considerable inhibition of production of superoxide radicals. Serum albumin, alcohol dehydrogenase, egg albumin, pepsin and trypsin enhance production of .O2- by this system. [A non-specific inhibition of the NBT reduction by various proteins used in the present investigation suggests that the superoxide dismutase-mediated reduction of Nishikimi's reaction is not quite specific; careful consideration of these factors should be taken while studying the superoxide dismutase activity by this method].