Steroid compounds have many important physiological activities in higher organisms. Testosterone and related steroids are important environmental contaminants that disrupt the endocrine systems of animals. The degradation of steroids, especially under anoxic conditions, is challenging because of their complex chemical structure. A denitrifying γ-proteobacterium, Steroidobacter denitrificans, able to grow anaerobically on a variety of steroids as the sole carbon and energy source was adopted as a model organism to study the anoxic degradation of testosterone. We identified the initial intermediates involved in the anoxic testosterone degradation pathway of S. denitrificans. We demonstrated that under anoxic conditions, S. denitrificans initially oxidizes testosterone to 1-dehydrotestosterone, which is then transformed to androsta-1,4-diene-3,17-dione. In addition, it seems that androst-4-en-3,17-dione can also be directly produced from testosterone by S. denitrificans cells. In general, the initial steps of anoxic testosterone degradation by S. denitrificans are similar to those of the oxic pathway demonstrated in Comamonas testosteroni.
AndersonJ.,
IyaduriR.2003; Integrated urban water planning: big picture planning is good for the wallet and the environment. Water Sci Technol 47:19–23
ChiangY. R.,
IsmailW.,
MüllerM.,
FuchsG.2007; Initial steps in the anoxic metabolism of cholesterol by the denitrifying Sterolibacterium denitrificans. J Biol Chem 282:13240–13249
ChiangY. R.,
IsmailW.,
GallienS.,
HeintzD.,
Van DorsselaerA.,
FuchsG.2008; Cholest-4-en-3-one-Δ1-dehydrogenase: a flavoprotein catalyzing the second step in anoxic cholesterol metabolism. Appl Environ Microbiol 74:107–113
GromanE. V.,
EngelL. L.1977; Hydroxysteroid dehydrogenases of Pseudomonas testosteroni. Separation of a 17 beta-hydroxysteroid dehydrogenase from the 3(17) beta-hydroxysteroid dehydrogenase and comparison of the two enzymes. Biochim Biophys Acta 485:249–254
HanselmanT. A.,
GraetzD. A.,
WilkieA. C.2003; Manure-borne estrogens as potential environmental contaminants: a review. Environ Sci Technol 37:5471–5478
HorinouchiM.,
HayashiT.,
YamamotoT.,
KudoT.2003; A new bacterial steroid degradation gene cluster in Comamonas testosteroni TA441 which consists of aromatic-compound degradation genes for seco-steroids and 3-ketosteroid dehydrogenase genes. Appl Environ Microbiol 69:4421–4430
LackN. A.,
YamK. C.,
LoweE. D.,
HorsmanG. P.,
OwenR. L.,
SimE.,
EltisL. D.2010; Characterization of a carbon-carbon hydrolase from Mycobacterium tuberculosis involved in cholesterol metabolism. J Biol Chem 285:434–443
TarleraS.,
DennerE. B. M.2003; Sterolibacterium denitrificans gen. nov., sp. nov., a novel cholesterol-oxidizing, denitrifying member of the β-Proteobacteria. Int J Syst Evol Microbiol 53:1085–1091
van der GeizeR.,
YamK.,
HeuserT.,
WilbrinkM. H.,
HaraH.,
AndertonM. C.,
SimE.,
DijkhuizenL.,
DaviesJ. E.other authors2007; A gene cluster encoding cholesterol catabolism in a soil actinomycete provides insight into Mycobacterium tuberculosis survival in macrophages. Proc Natl Acad Sci U S A 104:1947–1952
WilliamsR. J.,
JohnsonA. C.,
SmithJ. J. L.,
KandaR.2003; Steroid estrogens profiles along river stretches arising from sewage treatment works discharges. Environ Sci Technol 37:1744–1750