Phosphorylation of NAD-dependent glutamate dehydrogenase from yeast.
The NAD-dependent glutamate dehydrogenase from Candida utilis was isolated from 32P-labeled cells following enzyme inactivation promoted by glutamate starvation and found to exist in a phosphorylated form. Analysis of purified, fully active NAD-dependent glutamate dehydrogenase (a form) and inactive NAD-dependent glutamate dehydrogenase (b form) for alkalilabile phosphate revealed that the a form contained 0.09 +/- 0.06 mol of phosphate/mol of enzyme subunit and b form 1.25 +/- 0.06 mol of phosphate/mol of enzyme subunit. Phosphorylation caused a 10-fold reduction in enzyme specific activity. Dephosphorylation (release of 32P) and enzyme reactivation occurred on incubation with cell-free yeast extracts, indicating the presence of a phosphoprotein phosphatase in such preparations.
D002175:Candida / Q000201:enzymology*; D004789:Enzyme Activation; D005969:Glutamate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D009243:NAD; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011233:Precipitin Tests
D010750:Phosphoproteins; D009243:NAD; D005969:Glutamate Dehydrogenase; D010749:Phosphoprotein Phosphatases