title: Utility of 3-O-methyl-N-acetyl-D-glucosamine, an N-acetylglucosamine kinase inhibitor, for accurate assay of glucokinase in pancreatic islets and liver.
abstract: Glucokinase, an enzyme that catalyzes the phosphorylation of glucose, constitutes the key regulatory step in glucose metabolism in pancreatic islets and liver. We found that 3-O-methyl-N-acetyl-D-glucosamine (3-O-methyl-GlcNAc) potently inhibits glucose phosphorylation by N-acetylglucosamine kinase whereas glucokinase is not at all affected by this hexosamine. The addition of 3-O-methyl-GlcNAc to the assay system for glucokinase in rat liver extracts, which contain a high activity of glucokinase (glucose as substrate) relative to N-acetylglucosamine kinase (N-acetyl-D-glucosamine as substrate), affected neither Km nor Vmax values of glucokinase. On the other hand, both Km and Vmax values of glucokinase in rat pancreatic islet extracts, in which N-acetylglucosamine kinase activity is higher than glucokinase activity, were significantly lowered by the use of 3-O-methyl-GlcNAc as an inhibitor of N-acetylglucosamine kinase.
authors.affiliation: Department of Clinical Biochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Miwa
authors.forename: Y
authors.initials: Y
authors.lastname: Mita
authors.forename: T
authors.initials: T
authors.lastname: Murata
authors.forename: J
authors.initials: J
authors.lastname: Okuda
authors.forename: M
authors.initials: M
authors.lastname: Sugiura
authors.forename: Y
authors.initials: Y
authors.lastname: Hamada
authors.forename: T
authors.initials: T
authors.lastname: Chiba
mesh_terms: D000117:Acetylglucosamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005941:Glucokinase / Q000302:isolation & purification / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D007515:Islets of Langerhans / Q000201:enzymology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; C014088:methyl-2-acetamido-2-deoxy-D-glucopyranoside; D017853:Phosphotransferases (Alcohol Group Acceptor); D005941:Glucokinase; C018716:N-acetylglucosamine kinase; D005947:Glucose; D000117:Acetylglucosamine