title: Metabolism of threo-beta-methylmalate by a soil bacterium.
abstract: Studies on threo-beta-methylmalate metabolism in a soil bacterium of the genus Bacillus which can utilize threo-beta-methylmalate as a sole carbon source were carried out. When DL-threo-beta-methylmalate was incubated with a cell-free extract of the bacterium, citramalate was found to be formed. Similarly, formation of threo-beta-methylmalate from DL-citramalate was confirmed. These dicarbosylic acids were identified by gas chromatography-mass spectrometry. Examination of inducibility, substrate specificity, and cofactor requirement of the enzymes involved in the reactions showed the existence of two interconversion reactions between the threo-beta-methylmalate and citramalate. One was an interconversion reaction between L-threo-beta-methylmalate and L-citramalate via mesaconate and the other was an interconversion reaction between D-threo-beta-methylmalate and D-citramalate via citraconate. These reactions were both reversible and were catalyzed by distinct and inducible enzymes. It is suggested that the two reactions participate in the catabolism of threo-beta-methylmalate.
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D002455:Cell Division; D002849:Chromatography, Gas; D007700:Kinetics; D008293:Malates / Q000378:metabolism*; D013058:Mass Spectrometry; D012987:Soil
chemical_list: D008293:Malates; D012987:Soil