Linked Life Data

1889417

Source:http://linkedlifedata.com/resource/pubmed/id/1889417

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-10-15
pubmed:abstractText
The regulatory protein of rat liver glucokinase (hexokinase IV or D) behaved as a fully competitive inhibitor of this enzyme when glucose was the variable substrate, i.e. it increased the half-saturating concentration of glucose as a linear function of its concentration without affecting V (velocity at infinite concentration of substrate). The inhibition by the regulatory protein and that by palmitoyl-CoA were synergistic with that by N-acetyl-glucosamine, indicating that the two former inhibitors bind to a site distinct from the catalytic site. In contrast, the effects of the regulatory protein and palmitoyl-CoA were competitive with each other, indicating that these two inhibitors bind to the same site. The regulatory protein exerted a non-competitive inhibition with respect to Mg-ATP at concentrations of this nucleotide less than 0.5 mM. At higher concentrations, the latter antagonized the inhibition by the regulatory protein partly by decreasing the apparent affinity for fructose 6-phosphate. The following anions inhibited glucokinase non-competitively with respect to glucose: Pi, sulfate, I-, Br-, No3-, Cl-, F- and acetate. Pi and sulfate, at concentrations in the millimolar range, decreased the inhibition by the regulatory protein by competing with fructose 6-phosphate. Monovalent anions also antagonized the inhibition by the regulatory protein with the following order of potency: I- greater than Br- greater than NO3- greater than Cl- greater than F- greater than acetate and their effect was non-competitive with respect to fructose 6-phosphate. Glucokinase from Buffo marinus and pig liver were, like the rat liver enzyme, inhibited by the regulatory protein, as well as by palmitoyl-CoA at micromolar concentrations. In contrast, neither compound inhibited hexokinases from rat brain, beef heart or yeast, or the low-Km specific glucokinase from Bacillus stearothermophilus.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
200
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
545-51
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Competitive inhibition of liver glucokinase by its regulatory protein.
pubmed:affiliation
Laboratoire de Chimie Physiologique, International Institute of Cellular and Molecular Pathology, Brussels, Belgium.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't