Kinetic properties and the mechanism of activation of NAD-dependent glutamate dehydrogenase from Dictyostelium discoideum.
Two forms of the NAD-dependent glutamate dehydrogenase were partially purified from Dictyostelium discoideum, an activated and a non-activated form. V(max) for the non-activated enzyme was stimulated 88-fold and the activated enzyme 3-fold by 0.1 mM AMP (at their pH optima). Half maximal stimulation by AMP is achieved at 221 +/- 39 microM for the non-activated enzyme and 20 +/- 2 microM for the activated enzyme. We have shown that activation of NAD-GDH in vivo has many similarities to trypsin treatment of non-activated enzyme and that proteolysis is the probable mechanism of activation.
Pamula
F
F
Faculty of Science and Engineering, School of Biological Sciences, Flinders University of South Australia, Adelaide, Australia.
Wheldrake
J F
JF
D000249:Adenosine Monophosphate / Q000494:pharmacology; D000586:Amination; D000818:Animals; D003641:Deamination; D004023:Dictyostelium / Q000201:enzymology*; D004789:Enzyme Activation; D005969:Glutamate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D009243:NAD / Q000378:metabolism*; D013268:Stimulation, Chemical; D014357:Trypsin / Q000494:pharmacology
D007527:Isoenzymes; D009243:NAD; D000249:Adenosine Monophosphate; D005969:Glutamate Dehydrogenase; D014357:Trypsin