Forty years ago Coulter and Talalay (A. In this study five additional intermediates of the anoxic pathway were identified. We demonstrated that subsequent steps of the anoxic pathway greatly differ from those of the established oxic pathway which suggests that a novel pathway for testosterone catabolism is present. In the proposed anoxic pathway a reduction reaction occurs at C-4 and C-5 of androsta-1 4 17 the last common intermediate of both the oxic and anoxic pathways. After that a novel hydration reaction occurs and a hydroxyl group is thus introduced to the C-1α position of C19steroid substrates. To our knowledge an enzymatic hydration reaction occurring at the A ring of steroid compounds has not been reported before. INTRODUCTION Isoprenoids are built up from one or more five-carbon units and constitute a large group of natural compounds. Among them cholesterol a triterpenoid is present in the membranes of eukaryotes and its major role is to modulate the toughness and permeability of membranes. In addition cholesterol also serves as a precursor to all steroid hormones vitamin D and bile acids (3). One of its derivatives testosterone belongs to the C19androgen group and is primarily secreted by the testes of males and ovaries of females. Compared to cholesterol the aliphatic side chain present on C-17 is absent from testosterone (for its structure see Fig. 1) rendering it even more drinking water soluble than its biosynthetic precursor. Mammals have the ability to synthesize but cannot degrade testosterone and various other steroid human hormones. After hook modification to improve the solubility AMG 900 these steroid UTP14C substances are excreted in to the environment through the urinary system (3). Fig. 1. Preliminary steps mixed up in catabolism of testosterone by bacterias. (A) Set up oxic pathway (7 17 (B) Suggested initial guidelines in the anoxic pathway as researched in S. denitrificansDSMZ18526. The proclaimed WPS4 and WPS3 will be the presumed intermediates … A number of androgens and estrogens AMG 900 have already been discovered in effluents of American Brazilian Canadian and German wastewater treatment plant life and in surface area drinking water in American and Dutch streams at concentrations in the ng liter?1range (2 18 20 32 Most steroid human hormones present in the surroundings are made by human beings and livestock (25). Among the main worries about these organic steroid hormones is certainly their capability to alter the intimate behavior and endocrine systems of animals (22 31 Due to the harmful environmental influences of steroid human hormones removing these substances from the surroundings has attracted raising interest (1). Latest research indicated that anoxic riverbed sediments and garden soil have the to be always a tank for steroid substances (13 33 Hence to be able to enhance the removal of steroids from the surroundings it’s important to comprehend the biochemical procedures involved with anoxic mineralization of steroid human hormones. In addition for their different physiological features in our body steroid substances may be positioned being among the most broadly marketed chemicals with the pharmaceutical sector (11). This curiosity is because of the biotechnological applications of steroid-transforming enzymes with high regio- and stereospecificity in the commercial synthesis of steroids AMG 900 (19). The complicated framework of steroid substances as well as AMG 900 the high regio- and stereoselectivity from the enzymatic reactions render the electricity of biocatalysts from microbial resources particularly fascinating. The entire oxic mineralization of testosterone by different species such as for example Comamonas testosteroniwas researched in some details (7 16 17 (Fig. 1A). The oxic catabolism of testosterone is set up by dehydrogenation from the 17β-hydroxyl group to create androst-4-en-3 17 which in turn goes through another dehydrogenation to create androsta-1 4 17 The subsequent cleavage of the core ring system is usually catalyzed by several oxygenases that utilize oxygen as a cosubstrate (12 16 17 26 (see also Fig. 1A). On the contrary little is known about the anoxic degradation of steroids (4). It is obvious that anaerobic microorganisms would have to utilize.