title: Repression by glucose of acetohydroxy acid synthetase in Escherichia coli B.
abstract: Acetolactate formation in Escherichia coli B results from the activity of a single system, acetohydroxy acid synthetase, which has a pH optimum of 8.0 and is sensitive to end-product inhibition by l-valine. Acetohydroxy acid synthetase was found to be subject to catabolite repression, and the nature and concentration of the carbon source had a greater effect on the formation of the enzyme than had the known end products (valine, isoleucine, leucine and pantothenate) of the biosynthetic pathways of which this enzyme is a member. The results suggest that acetohydroxy acid synthetase may play an amphibolic role in E. coli B.
mesh_terms: D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology*; D005947:Glucose / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007532:Isoleucine / Q000096:biosynthesis; D007773:Lactates / Q000096:biosynthesis; D007930:Leucine / Q000096:biosynthesis; D008025:Ligases / Q000378:metabolism*; D010205:Pantothenic Acid / Q000096:biosynthesis; D014633:Valine / Q000096:biosynthesis
chemical_list: D007773:Lactates; D007532:Isoleucine; D010205:Pantothenic Acid; D008025:Ligases; D007930:Leucine; D014633:Valine; D005947:Glucose; D005990:Glycerol