The effect of acetyl-coenzyme A on phosphate-activated glutaminase from pig kidney and brain.
Phosphate-activated glutaminase (EC 3.5.1.2; l-glutamine amidohydrolase) purified from pig kidney and brain is activated by CoA and short-chain acyl-CoA derivatives. Acetyl-CoA is the most powerful activator (K(A) about 0.2mm). Acetyl-CoA is maximally effective in the absence of other activating anions such as phosphate and citrate, and at low glutamine concentrations. The negative co-operative substrate activation observed at pH7 becomes more pronounced in the presence of acetyl-CoA. Similarly to phosphate, acetyl-CoA produces at high protein concentrations a different type of activation, which is time-dependent, depends on protein concentration and is accompanied by an increase in the sedimentation coefficient. Acetyl-CoA, phosphate and citrate appear to have binding sites in common. No significant difference was observed between kidney and brain phosphate-activated glutaminase.
D000105:Acetyl Coenzyme A; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology*; D002499:Centrifugation, Density Gradient; D002854:Chromatography, Paper; D002951:Citrates; D004789:Enzyme Activation; D005972:Glutaminase / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000201:enzymology*; D009243:NAD; D010710:Phosphates / Q000494:pharmacology; D013053:Spectrophotometry; D013552:Swine; D013997:Time Factors
D002951:Citrates; D010710:Phosphates; D009243:NAD; D000105:Acetyl Coenzyme A; D005972:Glutaminase