title: Synthesis and hydrolysis of malyl-coenzyme A by Pseudomonas AM1: an apparent malate synthase activity.
abstract: The malate synthase activity detectable in crude extracts of Pseudomonas AM1 has been shown to be due to a coupling of a malyl-CoA hydrolase with malyl-CoA lyase and not due to a discrete malate synthase enzyme. The partial purification of this malyl-CoA hydrolase from Pseudomonas AM1 has shown that it is distinct from citrate synthase which also hydrolyses malyl-CoA. The malyl-CoA hydrolase has a low Km for malyl-CoA (7-0 muM). A mutant of Pseudomonas AM1, ICT51 (Taylor & Anthony, 1975), which is unable to grow on ethanol, malonate or 3-hydroxybutyrate, has been shown to have an altered malyl-CoA hydrolase with a Km for malyl-CoA 30 times higher than that of the enzyme present in the wild-type organism. Two classes of revertants to growth on these substrates have been isolated: (i) those with a malyl-CoA hydrolase of similar Km to the wild-type and (ii) those in which the malyl-CoA hydrolase activity remains the same as in the mutant ICT51. The nature of the mutation leading to the latter class of revertants is unknown.
mesh_terms: D002474:Cell-Free System; D002950:Citrate (si)-Synthase / Q000378:metabolism; D003065:Coenzyme A / Q000096:biosynthesis / Q000378:metabolism*; D006867:Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D006885:Hydroxybutyrates / Q000378:metabolism; D000432:Methanol / Q000378:metabolism; D009154:Mutation; D007652:Oxo-Acid-Lyases / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology / Q000378:metabolism*; D013386:Succinates / Q000378:metabolism
chemical_list: D006885:Hydroxybutyrates; D013386:Succinates; D002950:Citrate (si)-Synthase; D006867:Hydrolases; D007652:Oxo-Acid-Lyases; D003065:Coenzyme A; D000432:Methanol