Sulphoconjugation of steroids in porcine liver. Partial purification of the cytosolic sulphotransferases for pregnenolone and 5 alpha-androst-16-en-3 beta-ol.

Steroid sulphotransferase activities for 5 alpha-androst-16-en-3 beta-ol and pregnenolone in porcine liver cytosol have been assayed using 3'-phosphoadenosine-5'-phospho[35S]sulphate as sulphate donor. 5 alpha-Androst-16-en-3 beta-ol sulphotransferase activity was obtained from porcine liver cytosol by gel filtration chromatography; activity was linear with time up to about 5 min., the optimum pH was near 8.0 and optimum temperature 37 degrees C. Pregnenolone sulphotransferase activity was partially purified from porcine liver cytosol using DEAE-cellulose chromatography with an ionic gradient of KC1. This enzyme activity was linear with time up to 10 min and had optimum pH and temperature of 8.0 and 37 degrees C, respectively.