Open AccessYeast Hexokinase: Interaction with Substrates and Analogs Studied by Difference Spectrophotometry
Author(s) -
Roustan Claude,
Brevet Annie,
Pradel LouiseAnne,
Van thoai Nguyen
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03492.x
Subject(s) - hexokinase , yeast , sugar , substrate (aquarium) , ternary complex , enzyme , chemistry , biochemistry , nucleotide , spectrophotometry , stereochemistry , chromatography , biology , glycolysis , ecology , gene
The mechanism of the reaction catalyzed by yeast hexokinase has been investigated by means of spectrophotometric investigations. Two binding sites, one for the sugar and one for the nucleotide substrate, have been characterized. The interaction of sugar substrates with yeast hexokinase induces spectral perturbations of aromatic residues of the protein molecule. The specificity of the enzyme towards its sugar substrates is discussed. The interaction of ATP‐Mg can only be visualized spectrophotometrically when the sugar substrate or inhibitor is already bound to the enzyme. Furthermore, spectrophotometric studies evidence the formation of a binary complex (sugar · enzyme) and ternary complexes (sugar · enzyme · nucleotide) in accord with an ordered mechanism.