Inhibitors and activators of brain hexokinase

Inhibitors and activators of brain hexokinase.

Activators of yeast hexokinase.

The rate of the ATP:glucose transphosphorylase reaction catalyzed by yeast hexokinase, isozyme PII, is inhibited by lowering the pH of the reaction below 7.0, especially at suboptimal concentrations of ATP. This effect of acidity is largely overcome by activators such as orthophosphate, citrate, malate, 3-phosphoglycerate, and riboside triphosphates. Thus, in the acid range, ATP appears to serv...

Effect of Activators and Inhibitors on Lactase Activities to Determine its Kinetic Model

High resolution crystal structures of yeast hexokinase complexes with substrates, activators, and inhibitors. Evidence for an allosteric control site.

The structures of both monomeric and dimeric yeast hexokinase complexed with sugar and nucleotide substrates and analogues have been determined at 3.5 to 2.7 b resolution. The most striking finding is that there are two kinds of nucleotide binding sites in the dimeric enzyme. We conclude that one kind of site, the A site, binds the ATP involved in the kinase reaction while the other site, the I...

Activators and inhibitors of lens aldose reductase.

Aldose reductase in a highly purified state is unstable. It requires the presence of thiol groups to maintain it in an active form. The enzyme apparently exists in 3 forms, only one of which is active. Tetramethylene glutaric acid (TMG) is an effective aldose reductase inhibitor. However, a relatively high level of TMG is needed to depress dulcitol synthesis in the lens incubated in a galactose...