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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1987-7-1
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pubmed:abstractText |
Characterization of glucokinase in pancreatic B-cells from ob/ob mice and from rat liver revealed identical characteristics. A narrow substrate specificity; high Km values for the two substrates, D-glucose and D-mannose, in the range of 10 and 20 mmol/l, respectively; higher Vmax values for D-glucose than for D-mannose; inhibition of glucokinase activities by D-mannoheptulose and by a specific glucokinase antibody. These characteristics distinguish glucokinase in soluble cytoplasmic fractions of pancreatic B-cells and liver from low Km hexokinases. Alloxan is a pancreatic B-cell cytotoxic agent, which has been widely used as a tool for the elucidation of the mechanisms of insulin secretion, because its inhibitory action on insulin secretion has been presumed to be intimately related to the mechanism of glucose-induced insulin secretion. Alloxan inhibited glucokinase but not hexokinase activity in cytoplasmic fractions of pancreatic B-cells and liver. The half maximal inhibitory concentration of alloxan was 5 mumol/l. Glucokinase activity was protected from alloxan toxicity only by D-glucose and D-mannose; the alpha anomer of D-glucose provided significantly greater protection than the beta anomer. The non-metabolizable sugar 3-O-methyl-D-glucose did not provide protection of glucokinase activity against inhibition by alloxan. Thus, inhibition of pancreatic B-cell glucokinase may contribute to the inhibition of glucose-induced insulin secretion by alloxan. These results support the contention that glucokinase regulates the metabolic flux rate through the glycolytic chain in the pancreatic B-cell and thereby generates the signal for glucose-induced insulin secretion.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Alloxan,
http://linkedlifedata.com/resource/pubmed/chemical/Glucokinase,
http://linkedlifedata.com/resource/pubmed/chemical/Glucose,
http://linkedlifedata.com/resource/pubmed/chemical/Hexokinase,
http://linkedlifedata.com/resource/pubmed/chemical/Mannose
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pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0001-5598
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
115
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
21-9
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:3296598-Alloxan,
pubmed-meshheading:3296598-Animals,
pubmed-meshheading:3296598-Cytoplasm,
pubmed-meshheading:3296598-Glucokinase,
pubmed-meshheading:3296598-Glucose,
pubmed-meshheading:3296598-Hexokinase,
pubmed-meshheading:3296598-Islets of Langerhans,
pubmed-meshheading:3296598-Liver,
pubmed-meshheading:3296598-Mannose,
pubmed-meshheading:3296598-Mice,
pubmed-meshheading:3296598-Mice, Obese,
pubmed-meshheading:3296598-Phosphorylation,
pubmed-meshheading:3296598-Rats,
pubmed-meshheading:3296598-Rats, Inbred Strains
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pubmed:year |
1987
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pubmed:articleTitle |
Glucokinase in pancreatic B-cells and its inhibition by alloxan.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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