title: Inhibition by orthophosphate esters of glucose-6-phosphatase.
abstract: Inhibition of rat liver microsomal glucose-6-phosphatase (D-glucose-6-phosphate phosphohydrolase, EC 3.1.3.9) by orthophosphate and organophosphate esters was examined at pH 6.0 and 7.5 with and without enzyme pretreatment with 0.2% (w/v) deoxycholate. Inhibition by orthophosphate and monoethyl phosphate was competitive with respect to glucose-6-P while inhibition by mono- and di-phenyl phosphate was of the mixed type. Monoalkyl phosphates were more effective inhibitors than the analogous di- and tri-alkyl phosphates and deoxycholate potentiated the inhibitory effects. Mono- and di-phenyl phosphates were more effective inhibitors than triphenyl phosphate, and deoxycholate decreased these inhibitory effects. The results are interpreted in terms of inhibitor and deoxycholate interactions with the enzyme.
mesh_terms: D000818:Animals; D003840:Deoxycholic Acid / Q000494:pharmacology; D005952:Glucose-6-Phosphatase / Q000037:antagonists & inhibitors*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D010755:Organophosphates / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D051381:Rats
chemical_list: D010755:Organophosphates; D009943:Organophosphorus Compounds; D003840:Deoxycholic Acid; D005952:Glucose-6-Phosphatase