Metabolism of 2,2'- and 3,3'-dihydroxybiphenyl by the biphenyl catabolic pathway of Comamonas testosteroni B-356.
The purpose of this investigation was to examine the capacity of the biphenyl catabolic enzymes of Comamonas testosteroni B-356 to metabolize dihydroxybiphenyls symmetrically substituted on both rings. Data show that 3,3'-dihydroxybiphenyl is by far the preferred substrate for strain B-356. However, the dihydrodiol metabolite is very unstable and readily tautomerizes to a dead-end metabolite or is dehydroxylated by elimination of water. The tautomerization route is the most prominent. Thus, a very small fraction of the substrate is converted to other hydroxylated and acidic metabolites. Although 2,2'-dihydroxybiphenyl is a poor substrate for strain B-356 biphenyl dioxygenase, metabolites were produced by the biphenyl catabolic enzymes, leading to production of 2-hydroxybenzoic acid. Data show that the major route of metabolism involves, as a first step, a direct dehydroxylation of one of the ortho-substituted carbons to yield 2,3,2'-trihydroxybiphenyl. However, other metabolites resulting from hydroxylation of carbons 5 and 6 of 2,2'-dihydroxybiphenyl were also produced, leading to dead-end metabolites.
Sondossi
M
M
Department of Microbiology, Weber State University, Ogden, Utah 84408, USA.
Barriault
D
D
Sylvestre
M
M
D001673:Biodegradation, Environmental; D001713:Biphenyl Compounds / Q000737:chemistry / Q000378:metabolism*; D020604:Comamonas testosteroni / Q000201:enzymology* / Q000254:growth & development; D003470:Culture Media; D006900:Hydroxylation; D010636:Phenols / Q000737:chemistry / Q000378:metabolism*
D001713:Biphenyl Compounds; D003470:Culture Media; D010636:Phenols; C038764:2,2'-biphenol