Propionyl-CoA carboxylase of Myxococcus xanthus: catalytic properties and function in developing cells.
An acyl-coenzyme A carboxylase that carboxylates acetyl-CoA, butyryl-CoA, propionyl-CoA, and succinyl-CoA was purified from Myxococcus xanthus. Since the enzyme showed maximal rates of carboxylation with propionyl-CoA, the enzyme is thought to be propionyl-CoA carboxylase. The apparent Km values for acetyl-CoA, butyryl-CoA, propionyl-CoA, and succinyl-CoA were found to be 0.2, 0. 2, 0.03, and 1.0 mM, respectively. The native enzyme has a molecular mass of 605-615 kDa and is composed of nonidentical subunits (alpha and beta) with molecular masses of 53 and 56 kDa, respectively. The enzyme showed maximal activity at pH 7.0-7.5 and at 25-30 degrees C, and was affected by variation in concentrations of ATP and Mg2+. During development of M. xanthus, the propionyl-CoA carboxylase activity increased gradually, with maximum activity observed during the sporulation stage. Previous work has shown that a propionyl-CoA-carboxylase-deficient mutant of M. xanthus reduces levels of long-chain fatty acids. These results suggest that the propionyl-CoA carboxylase is also responsible for the carboxylation of acetyl-CoA to malonyl-CoA used for the synthesis of long-chain fatty acids during development.
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-Cho, Kagawa, 761-07, Japan. kimura@ag.kagawa-u.ac.jp
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Kimura
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D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D015153:Blotting, Western; D019731:Carbon-Nitrogen Ligases; D002262:Carboxy-Lyases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D002384:Catalysis; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D043586:Methylmalonyl-CoA Decarboxylase; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016941:Myxococcus xanthus / Q000201:enzymology* / Q000254:growth & development; D016415:Sequence Alignment; D013171:Spores, Bacterial / Q000502:physiology
D015636:Magnesium Chloride; D000255:Adenosine Triphosphate; D002262:Carboxy-Lyases; D019731:Carbon-Nitrogen Ligases; C019791:biotin carboxylase; D043586:Methylmalonyl-CoA Decarboxylase