title: [Negative cooperativity of 6-phosphogluconate dehydrogenase in rat liver].
abstract: The effect of various NADPH concentrations on the activity of rat liver 6-phosphogluconate dehydrogenase (EC 1.1.1.44) has been studied. The influence of NADPH concentrations on the enzyme cooperativity was observed. NADPH used at concentration up to 200 microM appeared to be a competitive inhibitor with respect to NADP+ without any cooperative effect towards the coenzyme (NADP+) binding. At high concentrations of NADPH (above 300 microM) the negative cooperativity displayed by the enzyme was confirmed by a significant decrease of the Hill coefficient for NADP(+)-from 1.1 +/- 0.2 down to 0.6 +/- 0.1 (p < 0.05).
authors.forename: N E
authors.initials: NE
authors.lastname: Voĭnova
authors.forename: L S
authors.initials: LS
authors.lastname: Chesnokova
authors.forename: S N
authors.initials: SN
authors.lastname: Lyzlova
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D008099:Liver / Q000201:enzymology*; D008297:Male; D009249:NADP / Q000378:metabolism; D010734:Phosphogluconate Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats
chemical_list: D009249:NADP; D010734:Phosphogluconate Dehydrogenase
vernacular_title: Ob otritsatel'noĭ kooperativnosti 6-fosfogliukonatdegidrogenazy pecheni krys.