Further evidence for two distinct acetolactate synthetases in Aerobacter aerogenes

Halpern, Yeheskel S.; Even-Shoshan, Avivith

doi:10.1016/0005-2744(67)90053-8

Cited by 31 publications

(30 citation statements)

References 12 publications

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“…The level of a-acetohydroxyacid synthetase in valine-grown A . variabilis was certainly no lower than in minimally grown organisms and this contrasts with those bacteria where valine represses this enzyme (Halpern & Umbarger, 1959;Radhakrishnan & Snell, 1960). Neither threonine deaminase nor transaminase B were repressed when the three branched-chain amino acids were included in the growth medium of A .…”

Section: Discussionmentioning

confidence: 92%

Branched-chain Amino Acid Biosynthesis in the Blue-green Alga Anabaena variabilis

Hood

Carr

1972

Journal of General Microbiology

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SUMMARYFour enzymes (threonine deaminase, a-acetohydroxyacid synthetase, isopropylmalate synthetase and t ransaminase B) involved in leucine, isoleucine and valine synthesis have been detected in extracts of the blue-green alga Anabaena variabilis and the control of three of the enzymes examined. A new procedure for the determination of transaminase B is described. Threonine deaminase and a-acetohydroxyacid synthetase are subject to feedback control by their end-products. No evidence for the repression of enzyme synthesis in the pathway has been found, although the assimilation and incorporation of exogenous valine and leucine was demonstrated.

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Section: Discussionmentioning

confidence: 92%

Branched-chain Amino Acid Biosynthesis in the Blue-green Alga Anabaena variabilis

Hood

Carr

1972

Journal of General Microbiology

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“…This is similar to the case of Streptococcus jaecalis 13 ,14) but different from that of E. coli. 15 ) In view of the fact that inhibition by amino acids other than aspartate hardly occurred and inhibition by structural analogues was very weak in comparison with that by aspartate, the uptake system appears to be highly specific for glutamate and aspartate.…”

Section: Discussionmentioning

confidence: 99%

Glutamate Transport and Production inBrevibacterium flavum

Mori

Shiio

1983

Agricultural and Biological Chemistry

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“…They were deficient in the pH 6 acetolactate-forming enzyme (E,) and butyleneglycol dehydrogenase (E,) activity, and mutant 45-111, in addition had a block in acetolactate decarboxylase (E,) activity. The bacteria were grown in minimal media as described [11,12], and strain 1033, for purification of the enzyme, was grown as reported [7].…”

Section: Buffersmentioning

confidence: 99%

The Reduction of Diacetyl and Acetoin in Aerobacter aerogenes

Bryn

Hetland

Størmer

1971

European Journal of Biochemistry

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The reduction of diacetyl and acetoin has been shown to be catalyzed by one enzyme in Aerobacter aerogenes. The ratio of the two activities remains constant during purification into homogeneity, and the t3wo activities appear in the same amount when the growing cells are exposed to acetate.Juni [i] showed in 1952 that acetoin (acetylmethyl carbinol) is formed by a sequence of two enzymes in Aerobacter aerogenes, one catalyzing the formation of acetolactate from pyruvate, and another decarboxylating acetolactate to yield acetoin. These enzymes, the p H 6 acetolactateforming enzyme (El) and acetolactate decarboxylase (E2) have been purified and characterized [2-81.Strecker and Harary [9] described in 1954 two enzyme systems from A . aerogenes and Xtaphylococcus aureus, one catalyzing the reversible oxidation by NAD of 2,3-butanediol to acetoin, and the other cata.1yzing an essentially irreversible reduction by NADH of diacetyl to acetoin. These enzymes, butyleneglycol dehydrogenase ( E3) and diacetyl reductase (E,) were partially purified, and they suggested that these enzymes were different. The formation of acetoin and 2,3-butanediol is shown in Fig. 1 25", for measurement of butyleneglycol dehydrogenase activity [9], consist, in a total volume of 3 ml, of the following amounts per ml: 0.1 pmole NAD, 13 pmoles 2,3-butanediol, 50 pmoles phosphate pH 7.0 and enzyme. For measurement of diacetyl reductase activity, the 1 ml mixture contained 0.i pmole NADH, 13 pmoles diacetyl, 50 pmoles phosphate pH 7.5 and enzyme. A unit is defined as that amount of enzyme that gives a change in absorbance a t 340nm of 0.001 per min at 25".A Beckman DB recording spectrophotometer was used for these assays. For stability of the enzyme upon dilution, see Results. ProteinProtein was determined by the method of Lowry et al. [lo] and for purified preparation with low protein concentration, by the absorbance a t 280 nm. Protein bands in polyacrylamide gels were strained with 0.lo/, amidoblack in 50/, acetic acid, 5O/, methyl alcohol, and water. BuffersThe standard buffers, prepared a t 20", used throughout this work were the following: 50 mM phosphate containing 0.1 mM NAD and 25 mM 2-mercaptoethanol pH 7.0, and 50 mM Tris-C1 containing 0.1 mM NAD and 25 mM 2-mercaptoethanol

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Further evidence for two distinct acetolactate synthetases in Aerobacter aerogenes

Cited by 31 publications

References 12 publications

Branched-chain Amino Acid Biosynthesis in the Blue-green Alga Anabaena variabilis

Branched-chain Amino Acid Biosynthesis in the Blue-green Alga Anabaena variabilis

Glutamate Transport and Production inBrevibacterium flavum

The Reduction of Diacetyl and Acetoin in Aerobacter aerogenes

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