title: Identification of camphor oxidation and reduction products in Pseudomonas putida: new activity of the cytochrome P450cam system.
abstract: P450 enzymes are known for catalyzing hydroxylation reactions of non-activated C-H bonds. For example, P450(cam) from Pseudomonas putida oxidizes (1R)-(+)-camphor to 5-exo-hydroxy camphor and further to 5-ketocamphor. This hydroxylation reaction proceeds via a catalytic cycle in which the reduction of dioxygen (O(2)) is coupled to the oxidation of the substrate. We have observed that under conditions of low oxygen, P. putida and isolated P450(cam) reduce camphor to borneol. We characterized the formation of borneol under conditions of low oxygen or when the catalytic cycle is shunted by artificial oxidants like m-chloro perbenzoic acid, cumene hydroperoxide, etc. We also tested the toxicity of camphor and borneol with P. putida and Escherichia coli. We have found that in P. putida borneol is less toxic than camphor, whereas in E. coli borneol is more toxic than camphor. We discuss a potental ecological advantage of the camphor reduction reaction for P. putida.
authors.affiliation: Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A1S6.
authors.forename: Brinda
authors.initials: B
authors.lastname: Prasad
authors.forename: Adina
authors.initials: A
authors.lastname: Rojubally
authors.forename: Erika
authors.initials: E
authors.lastname: Plettner
mesh_terms: D001892:Camphanes / Q000378:metabolism / Q000633:toxicity; D002164:Camphor / Q000378:metabolism* / Q000633:toxicity; D019475:Camphor 5-Monooxygenase / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D010084:Oxidation-Reduction; D016958:Pseudomonas putida / Q000378:metabolism*; D023382:Toxicity Tests, Acute
chemical_list: D001892:Camphanes; D003580:Cytochromes; D002164:Camphor; D019475:Camphor 5-Monooxygenase; C022871:isoborneol