Binding of ATP at the active site of human pancreatic glucokinase--nucleotide-induced conformational changes with possible implications for its kinetic cooperativity.

ABSTRACT: Glucokinase (GK) is the central player in glucose-stimulated insulin release from pancreatic β-cells, and catalytic activation by α-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. Here, we report on a conformational change induced by the binding of adenine nucleotides to human pancreatic GK, as determined by intrinsic tryptophan fluorescence, using the catalytically inactive mutant form T228M to correct for the inner filter effect. Adenosine-5'-(β,γ-imido)triphosphate and ATP bind to the wild-type enzyme with apparent [L](0.5) (ligand concentration at half-maximal effe

SUBMITTER: Molnes J 

PROVIDER: S-EPMC3531626 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature