Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT00841 (Cibacron Blue)
 478 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glucose 6-phosphotransferases were investigated in two transplantable rat insulinoma tumor lines. Homogenates of tumors contained glucose phosphorylating activities of both high (e.g. supernatant Km = 0.060 mM and pellet Km = 0.077 mM) and low (Km = 7.6 mM) affinities for glucose. Chromatography of supernatants (105,000 X g) of insulinomas on DEAE-Cibacron Blue F3GA agarose evidenced glucose 6-phosphotransferase activity which eluted similarly to glucokinase from rat liver. Kinetic studies of insulinoma glucokinase also indicated similarity with liver glucokinase, i.e. cooperative rate dependence on glucose concentration and comparable Km values for glucose, and it did not phosphorylate N-acetylglucosamine. These characteristics of glucose 6-phosphotransferase in insulinomas are similar to those of the enzyme found in islets of Langerhans. Since glucokinase is thought to serve as glucose sensor of insulin secretory pancreatic beta-cells, these transplantable insulinomas offer great promise for biochemical and biophysical studies of the nature of glucose-induced insulin release.
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PMID:Identification and significance of glucokinase in transplantable insulinomas. 629 27

Glucokinase from rat liver or transplantable, radiation-induced insulinomas was partially purified by ion exchange chromatography using DEAE-Cibacron Blue F3GA agarose. Phosphorylation of alpha,beta-D-mannose by glucokinase occurred with cooperative rate dependence on mannose concentration (nH: 1.50). Half-maximal phosphorylation rate occurred at 14 mM alpha,beta-D-mannose. The alpha- and beta-anomers of mannose were phosphorylated with sigmoidal kinetics (nH: 1.57 and 1.42, respectively). The affinity of glucokinase for alpha-D-mannose is higher than for beta-D-mannose (S0.5: 12 mM versus 19 mM). The maximum phosphorylation rate is slightly higher, about 10%, with beta-D-mannose than with alpha-D-mannose. Islet glucokinase has previously been shown to be chromatographically and kinetically identical to glucokinase from insulinoma and liver; therefore, evidence that glucokinase from these two tissues phosphorylates mannose with cooperative rate dependence and differentiates mannose anomers supports the glucokinase-glucose sensor hypothesis.
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PMID:Mannose phosphorylation by glucokinase from liver and transplantable insulinoma. Cooperativity and discrimination of anomers. 631