Purification and properties of bile acid sulfate sulfatase from Pseudomonas testosteroni

The bile acid sulfate sulfatase (BSS) produced by Pseudomonas testosteroni was purified and characterized. Chromatofocusing behavior and amino acid sequence over twelve amino acid residues from N-terminus of the enzyme indicated that BSS was composed of two isoforms of which molecular weights were 125,000 and 103,000. Each isoform was a homodimer of a subunit of which molecular weight was 53,000 or 51,000, respectively. The optimum pH was 8.5 and BSS was stable at pH 5.8-8.0. The thermostability above 32 degrees C was improved by the addition of polyols, such as sorbitol, sucrose, and glycerol. BSS was a Mn(2+)-dependent enzyme and contained 1-2 atoms of manganese in its own protein molecule. All 3 alpha-sulfate esters of the bile acids routinely appearing in human serum were hydrolyzed by BSS to 3 beta-hydroxyl iso-compounds corresponding to each bile acid and sulfuric acid. We tentatively named this novel enzyme BSS (bile acid 3 alpha-sulfate sulfohydrolase).