Guinea-pig intestinal sulphotransferases: an investigation using the cytosol fraction

A rat liver cytosol preparation fortified with a PAPS regenerating system has been used to study enzymically mediated sulpha conjugation of several phenols. In agreement with previous findings with isolated intestinal epithelial cells and hepatocytes from rats 2-hydroxybiphenyl was poorly sulphated compared with 4-hydroxybiphenyl and 7-hydroxycoumarin. The results are attributed to the involvement of different sulphotransferases in the conjugation of these substrates. Examination of the effects of changing pH and substrate concentration indicated that at least two sulphotransferases are probably involved in the sulphation of 2-hydroxybiphenyl and four sulphotransferases participate in the sulphation of 4-hydroxybiphenyl.