Chymotryptic activation of glutamate dehydrogenase.
Treatment of bovine liver glutamate dehydrogenase (L-glutamate:NAD(P)+ oxidoreductase (deaminating), EC 1.4.1.3) with chymotrypsin generates a proteolytic derivative that is activated 3-4-fold over the native enzyme. Stable preparations of activated enzyme show altered kinetic parameters (5-fold increase in Km for glutamate, 3-fold increase in Vmax) and altered response to allosteric modulation by GTP and ADP. The proteolysed enzyme was less responsive to GTP and was no longer activated by ADP, although ADP binding sites remained intact on the enzyme. The effect of ADP upon substrate inhibition was altered and negative homotropic interactions in coenzyme binding were abolished.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000494:Allosteric Regulation; D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism*; D004789:Enzyme Activation; D005969:Glutamate Dehydrogenase / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D011485:Protein Binding
D006153:Guanosine Diphosphate; D000244:Adenosine Diphosphate; D005969:Glutamate Dehydrogenase; D002918:Chymotrypsin