Biomaterial Database

Control of acetohydroxy acid synthetase in Escherichia coli 9723. 1978

D A Wiginton, and W Shive

A method by which three acetohydroxy acid synthetase activities are separated from extracts of Escherichia coli 9723 has been developed. Isoleucine specifically represses synthesis of one of the enzymes, which is not sensitive to valine inhibition, and isoleucine also simultaneously enhances the production of a second activity, which is valine inhibitable. The valine-inhibitable activity is repressed by leucine and valine, a combination of which is more effective than either alone. The third acetohydroxy acid synthetase, which is more active at pH 6 than at 8, is not controlled by the branched-chain amino acids. In a mutant of E. coli 9723 selected for the ability of valine to inhibit growth, the isoleucine-repressible acetohydroxy acid synthetase activity was no longer present, but isoleucine addition still resulted in enhanced production of the valine-inhibitable activity.

UI	MeSH Term	Description	Entries
D007652	Oxo-Acid-Lyases	Enzymes that catalyze the cleavage of a carbon-carbon bond of a 3-hydroxy acid. (Dorland, 28th ed) EC 4.1.3.	Ketoacid-Lyases,Ketoacid Lyases,Oxo Acid Lyases
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D004794	Enzyme Repression	The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.	Repression, Enzyme
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000095	Acetolactate Synthase	A flavoprotein enzyme that catalyzes the formation of acetolactate from 2 moles of PYRUVATE in the biosynthesis of VALINE and the formation of acetohydroxybutyrate from pyruvate and alpha-ketobutyrate in the biosynthesis of ISOLEUCINE. This enzyme was formerly listed as EC 4.1.3.18.	Acetohydroxy Acid Synthase,Acetohydroxy Acid Synthetase,Acetolactate Synthetase,Acetohydroxyacid Synthetase I,Acetoxyhydroxyacid Synthase III,Acid Synthase, Acetohydroxy,Acid Synthetase, Acetohydroxy,Synthase III, Acetoxyhydroxyacid,Synthase, Acetohydroxy Acid,Synthase, Acetolactate,Synthetase I, Acetohydroxyacid,Synthetase, Acetohydroxy Acid,Synthetase, Acetolactate