Metabolism of cyclohexaneacetic acid and cyclohexanebutyric acid by Arthrobacter sp. strain CA1.
A strain of Arthrobacter was isolated by enrichment culture with cyclohexaneacetate as the sole source of carbon and grew with a doubling time of 4.2 h. In addition to growing with cyclohexaneacetate, the organism also grew with cyclohexanebutyrate at concentrations not above 0.05%, and with a variety of alicyclic ketones and alcohols. Oxidation of cyclohexaneacetate proceeded through formation of the coenzyme A (CoA) ester followed by initiation of a beta-oxidation cycle. beta-Oxidation was blocked before the second dehydrogenation step due to the formation of a tertiary alcohol, and the side chain was eliminated as acetyl-CoA by the action of (1-hydroxycyclohexan-1-yl)acetyl-CoA lyase. The cyclohexanone thus formed was degraded by a well-described route that involves ring-oxygen insertion by a biological Baeyer-Villiger oxygenase. All enzymes of the proposed metabolic sequence were demonstrated in cell-free extracts. Arthrobacter sp. strain CA1 synthesized constitutive beta-oxidative enzymes, but further induction of enzymes active toward cyclohexaneacetate and its metabolites could occur during growth with the alicyclic acid. Other enzymes of the sequence, (1-hydroxycyclohexan-1-yl)acetyl-CoA lyase and enzymes of cyclohexanone oxidation, were present at negligible levels in succinate-grown cells but induced by growth with cyclohexaneacetate. The oxidation of cyclohexanebutyrate was integrated into the pathway for cyclohexaneacetate oxidation by a single beta-oxidation cycle. Oxidation of the compound could be divided into two phases. Initial oxidation to (1-hydroxycyclohexan-1-yl)acetate could be catalyzed by constitutive enzymes, whereas the further degradation of (1-hydroxycyclohexan-1-yl)acetate was dependent on induced enzyme synthesis which could be inhibited by chloramphenicol with the consequent accumulation of cyclohexaneacetate and (1-hydroxycyclohexan-1-yl)acetate.
D000085:Acetates / Q000378:metabolism*; D001173:Arthrobacter / Q000378:metabolism*; D002087:Butyrates / Q000378:metabolism*; D019755:Carbon-Carbon Lyases; D003066:Coenzyme A Ligases / Q000378:metabolism; D003510:Cyclohexanes; D003512:Cyclohexanones / Q000378:metabolism; D006836:Hydro-Lyases / Q000378:metabolism; D007700:Kinetics; D008190:Lyases / Q000378:metabolism; D010084:Oxidation-Reduction
D000085:Acetates; D002087:Butyrates; D003510:Cyclohexanes; D003512:Cyclohexanones; C034707:cyclohexanebutyric acid; D008190:Lyases; D019755:Carbon-Carbon Lyases; C034712:(1-hydroxycyclohexan-1-yl)acetyl-CoA lyase; D006836:Hydro-Lyases; C034711:cyclohexylideneacetyl-CoA hydratase; D003066:Coenzyme A Ligases; C034713:cyclohexaneacetyl-CoA synthetase; C018883:cyclohexaneacetic acid