title: Physiological function of the Pseudomonas putida PpG6 (Pseudomonas oleovorans) alkane hydroxylase: monoterminal oxidation of alkanes and fatty acids.
abstract: Pseudomonas putida PpG6 is able to utilize purified n-alkanes of six to ten carbon atoms for growth. It can also grow on the primary terminal oxidation products of these alkanes and on 1-dodecanol but not on the corresponding 2-ketones or 1,6-hexanediol, adipic acid, or pimelic acid. Revertible point mutants can be isolated which have simultaneously lost the ability to grow on all five n-alkane growth substrates but which can still grow on octanol or nonanol. An acetate-negative mutant defective in isocitrate lysase activity is unable to grow on even-numbered alkanes and fatty acids. Analysis of double mutants defective in acetate and propionate or in acetate and glutarate metabolism shows that alkane carbon is assimilated only via acetyl-coenzyme A and propionyl-coenzyme A. These results support the following conclusions: (i) The n-alkane growth specificity of P. putida PpG6 is due to the substrate specificity of whole-cell alkane hydroxylation; (ii) there is a single alkane hydroxylase enzyme complex; (iii) the physiological role of this complex is to initiate the monoterminal oxidation of alkane chains; and (iv) straight-chain fatty acids from butyric through nonanoic are degraded exclusively by beta-oxidation from the carboxyl end of the molecule.
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D002264:Carboxylic Acids / Q000378:metabolism; D002474:Cell-Free System; D003998:Dicarboxylic Acids / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D006900:Hydroxylation; D007523:Isocitrates; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D009153:Mutagens; D009154:Mutation; D009604:Nitrosoguanidines; D010084:Oxidation-Reduction; D007652:Oxo-Acid-Lyases / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity
chemical_list: D000473:Alkanes; D002264:Carboxylic Acids; D003998:Dicarboxylic Acids; D005227:Fatty Acids; D007523:Isocitrates; D009097:Multienzyme Complexes; D009153:Mutagens; D009604:Nitrosoguanidines; D006899:Mixed Function Oxygenases; D007652:Oxo-Acid-Lyases