Stereoselective formation of a K-region dihydrodiol from phenanthrene by Streptomyces flavovirens.
The metabolism of phenanthrene, a polycyclic aromatic hydrocarbon (PAH), by Streptomyces flavovirens was investigated. When grown for 72 h in tryptone yeast extract broth saturated with phenanthrene, the actinomycete oxidized 21.3% of the hydrocarbon at the K-region to form trans-9,10-dihydroxy-9,10-dihydrophenanthrene (phenanthrene trans-9,10-dihydrodiol). A trace of 9-phenanthrol was also detected. Metabolites isolated by thin-layer and high performance liquid chromatography were identified by comparing chromatographic, mass spectral, and nuclear magnetic resonance properties with those of authentic compounds. Experiments using [9-14C]phenanthrene showed that the trans-9,10-dihydrodiol had 62.8% of the radioactivity found in the metabolites. Circular dichroism spectra of the phenanthrene trans-9,10-dihydrodiol indicated that the absolute configuration of the predominant enantiomer was (-)-9S,10S, the same as that of the principal enantiomer produced by mammalian enzymes. Incubation of S. flavovirens with phenanthrene is an atmosphere of 18O2, followed by gas chromatographic/mass spectral analysis of the metabolites, indicated that one atom from molecular oxygen was incorporated into each molecule of the phenanthrene trans-9,10-dihydrodiol. Cytochrome P-450 was detected in 105,000 x g supernatants prepared from cell extracts of S. flavovirens. The results show that the oxidation of phenanthrene by S. flavovirens was both regio- and stereospecific.
Sutherland
J B
JB
National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079.
Freeman
J P
JP
Selby
A L
AL
Fu
P P
PP
Miller
D W
DW
Cerniglia
C E
CE
D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D008401:Gas Chromatography-Mass Spectrometry; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010616:Phenanthrenes / Q000378:metabolism*; D013302:Streptomyces / Q000378:metabolism*
D010616:Phenanthrenes