Multiple acyl-coenzyme A carboxylases in Pseudomonas citronellolis.
Pseudomonas citronellolis was shown to contain four different acyl-coenzyme A carboxylases, including acetyl-, propionyl-, 3-methylcrotonyl-, and geranyl-CoA carboxylases, when grown on the appropriate carbon sources. Acetyl-CoA carboxylase activity in crude extracts was stimulated approximately 40-fold by inclusion of 0.4-0.5 M ammonium sulfate in the assay. Unexpectedly high levels of propionyl-CoA carboxylase activity, also stimulated by ammonium sulfate, were found in acetate-grown cells. That these acetyl- and propionyl-CoA carboxylase activities were due to different enzymes was shown by their resolution during purification by a procedure that stabilized acetyl-CoA carboxylase as a complex and separated propionyl-CoA carboxylase into two required protein fractions. Propionate- or valine-grown cells contained a propionyl-CoA carboxylase activity that was strongly inhibited by ammonium sulfate in the assay, and which may represent an inducible form of the enzyme. Geranyl- and 3-methylcrotonyl-CoA carboxylases that catalyze the carboxylation of the 3-methyl groups of homologous acyl-CoA acceptors, were induced by growth on the monoterpenes, citronellic or geranoic acid; only 3-methylcrotonyl-CoA carboxylase was induced by growth on leucine or isovaleric acid. Induction of either carboxylase was associated with the appearance of similar high-molecular-weight, biotin-containing proteins as measured by gel filtration. These two carboxylases are probably distinct enzymes since 3-methyl-crotonyl-CoA carboxylase from isovalerate-grown cells does not carboxylate geranyl-CoA, while geranyl-CoA carboxylase will carboxylate both acyl-CoA homologues. P. citronellolis appears to be a useful system for studying the structural aspects of pairs of homologous acyl-CoA carboxylases.
D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000645:Ammonium Sulfate / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008025:Ligases / Q000302:isolation & purification / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology*
D007527:Isoenzymes; D008025:Ligases; D000103:Acetyl-CoA Carboxylase; D000645:Ammonium Sulfate