Inactivation of pyruvate decarboxylase by 3-hydroxypyruvate.
Pyruvate decarboxylase from Zymomonas mobilis is inhibited by 3-hydroxypyruvate, which can also act as a poor substrate. While catalysing the decarboxylation of this alternative substrate, the enzyme undergoes a progressive but partial inactivation over several hours. The extent of inactivation depends upon the pH and upon the concentration of 3-hydroxypyruvate. After partial inactivation and removal of unchanged 3-hydroxypyruvate, enzymic activity recovers slowly. We suggest that inactivation results from accumulation of enzyme-bound glycollaldehyde, which is relatively stable, possibly because it is dehydrated to form an acetyl group.
Thomas
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G
Department of Biochemistry, University of Queensland, St. Lucia, Australia.
Diefenbach
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R
Duggleby
R G
RG
D001667:Binding, Competitive; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors*; D004789:Enzyme Activation / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D011767:Pyruvate Decarboxylase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism / Q000494:pharmacology*
D011773:Pyruvates; C012375:hydroxypyruvic acid; D002262:Carboxy-Lyases; D011767:Pyruvate Decarboxylase