title: Triton X-100 inhibition of yeast plasma membrane associated NADH-dependent redox activities.
abstract: Plasma membrane (PM) vesicles isolated from the yeast Saccharomyces cerevisiae (wild-type NCIM 3078, and a MG 21290 mutant pma 1-1) were used to monitor the effect of the detergents, 3-[(3-cholamidopropyl) dimethylammonio]-1-propane sulfonate (Chaps) and Triton X-100, on (H+)-ATPase (E.C. 3.6.1.35), NADH oxidase and NADH-hexacynoferrate (III)[HCF (III)] oxidoreductase (E.C. 1.6.99.3) activities. The results obtained show that Triton X-100 inhibited both membrane bound and solubilized NADH-dependent redox activities. The nature of this inhibition as determined for NADH-HCF(III) oxidoreductase was non-competitive and the Ki values for wild and mutant enzymes were 1.2 x 10(-5) M and 8.0 x 10(-6) M, respectively. The findings are interpreted, in view of the established reports, that the active site architecture of PM bound NADH-dependent oxidoreductase in yeast is likely to be different than in other eukaryotes.
authors.affiliation: Department of Biochemistry, Lucknow University, Lucknow-226 007, India.
authors.forename: Vineet
authors.initials: V
authors.lastname: Awasthi
authors.forename: Snehlata
authors.initials: S
authors.lastname: Pandit
authors.forename: Prakash C
authors.initials: PC
authors.lastname: Misra
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001665:Binding Sites; D002462:Cell Membrane / Q000201:enzymology* / Q000378:metabolism; D002793:Cholic Acids / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007700:Kinetics; D009097:Multienzyme Complexes / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D017830:Octoxynol / Q000494:pharmacology*; D010084:Oxidation-Reduction; D011485:Protein Binding; D006180:Proton-Translocating ATPases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D002793:Cholic Acids; D003902:Detergents; D004791:Enzyme Inhibitors; D009097:Multienzyme Complexes; D017830:Octoxynol; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D000251:Adenosine Triphosphatases; D006180:Proton-Translocating ATPases; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate