Abstract
Induction of the enzymes involved in fatty acid β-oxidation in Pseudomonas fragi B-0771 cells grown in a medium containing straight chain saturated fatty acids was studied. The acyl-CoA dehydrogenase (ACDH) activity was induced during the exponential phase in cells grown in palmitic acid-supplemented medium, reached a maximum at the early stationary phase, and then gradually decreased thereafter. Changes in the overall activities of 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase, both existing on the multienzyme complex (HDT) involved in fatty acid β-oxidation, were similar to that in ACDH activity. Straight chain saturated fatty acids having more than 6 carbon atoms could induce both the ACDH and HDT activities, and C13-C15 fatty acids caused the greatest induction of both activities. Changes in the overall activities of 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase correlated with that in the amount of the α-subunit of HDT during the entire culture period in the medium containing palmitic acid. Surprisingly, the stoichiometry of the α- and β-subunit proteins of HDT was not maintained into the stationary phase culture, though the genes encoding the α- and β-subunits are tandemly coded in bacterial genomic DNA.
