Glucokinase (GK) is the central player in glucose-stimulated insulin release
from pancreatic b-cells, and catalytic activation by a-D-glucose binding has
a key regulatory function. Whereas the mechanism of this activation is well
understood, on the basis of crystal structures of human GK, there are no
similar structural data on ATP binding to the ligand-free enzyme and how
it affects its conformation.
a-d-Glucose activates glucokinase (EC 18.104.22.168) on its binding to the active
site by inducing a global hysteretic conformational change. Using intrinsic
tryptophan fluorescence as a probe on the a-d-glucose induced conforma-tional changes in the pancreatic isoform 1 of human glucokinase, key resi-dues involved in the process were identified by site-directed mutagenesis.
In several archaea of the Euryarchaeota, the glycolytic flux proceeds
through a modified version of the Embden–Meyerhof pathway, where the
phosphofructokinase and glucokinase enzymes use ADP as the phosphoryl
donor. These enzymes are homologous to each other. In the hyperthermo-philic methanogenic archaeon
Pharmacological activation or overexpression of glucokinase in hepatocytes
stimulates glucose phosphorylation, glycolysis and glycogen synthesis. We
used an inhibitor of glucose 6-phosphate (Glc6P) hydrolysis, namely the
chlorogenic derivative, 1-[2-(4-chloro-phenyl)-cyclopropylmethoxy]-3, 4-di-hydroxy-5-(3-imidazo[4,5-b]pyridin-1-yl-3-phenyl-acryloyloxy)-cyclohexane-
To gain better insight into the insulin secretory activity of
fetalbcells in response to glucose, the expression of glucose
transporter 2 (GLUT-2), glucokinase and mitochondrial
glycerol phosphate dehydrogenase (mGDH) were studied.
Expression ofGLUT-2mRNA and protein in pancreatic
islets and liver was signi®cantly lower in fetal and suckling
rats than in adult rats.