Citation

Duggleby RG. J. Enzyme Inhib. Med. Chem. 2005; 20(1): 1-4.

Copyright

(Copyright © 2005, Informa - Taylor and Francis Group)

DOI

10.1080/14756360400020553

PMID

15895677

Abstract

Acetohydroxyacid synthase (Ec 2.2.1.6) catalyses the thiamine diphosphate-dependent reaction between two molecules of pyruvate yielding 2-acetolactacte and CO2. The enzyme will also utilise hydroxypyruvate with a k(cat) value that is 12% of that observed with pyruvate. When hydroxypyruvate is the substrate, the enzyme undergoes progressive inactivation with kinetics that are characteristic of suicide inhibition. It is proposed that the dihydroxyethyl-thiamine diphosphate intermediate can expel a hydroxide ion forming an enol that rearranges to a bound acetyl group.

Language: en

Keywords

Acetolactate Synthase; Catalysis; Escherichia coli; Flavin-Adenine Dinucleotide; Kinetics; Pyruvates; Recombinant Proteins; Substrate Specificity; Thiamine Pyrophosphate