Inactivation of pyruvate decarboxylase by 3-hydroxypyruvate. |
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Authors: | G Thomas R Diefenbach R G Duggleby |
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Affiliation: | Department of Biochemistry, University of Queensland, St. Lucia, Australia. |
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Abstract: | 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. |
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