title: Activation and inhibition of phosphoglycerate kinase by sulphate ion.
abstract: A kinetic study of the effects of SO4(2-) in the activity of phosphoglycerate kinase (ATP: 3-phospho-D-glycerate 1-phosphotransferase, EC 2.7.2.3) is presented. SO4(2-) behaves both as an activator and inhibitor of the reaction. Activation does not appear to affect binding of one or the other of the two substrates to the catalytic centre. As an inhibitor SO4(2-) competes with both the substrates. Thus, each substrate can constrict SO4(2-) from the inhibitor binding site, probably the catalytic centre. Under these conditions activation becomes more and more evident. There appear to exist at least two SO4(2-) binding sites, one which earlier has been defined as an anion binding site, and a second, being the catalytic centre. The former seems to have a higher affinity for SO4(2-) than the latter.
mesh_terms: D000838:Anions / Q000494:pharmacology; D001665:Binding Sites; D004789:Enzyme Activation; D007700:Kinetics; D010735:Phosphoglycerate Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D013431:Sulfates / Q000494:pharmacology*
chemical_list: D000838:Anions; D013431:Sulfates; D010735:Phosphoglycerate Kinase