Sulphation of hydroxybiphenyls in human tissues

1. Sulphotransferase is an important detoxication pathway of hydroxybiphenyls and the kinetics of sulphotransferase activity were studied in human liver, ileum and colon mucosae, lung, kidney, urinary bladder mucosa and brain using 0-, m- and p-hydroxybiphenyl as substrates. 2. Sulphotransferase activity was detectable in all tissues studied, although it showed marked tissue-dependence. The rate of sulphation ranged greater than 100-fold in different tissues and the highest and lowest activities of sulphotransferase were found in liver and brain, respectively. 3. The Km of sulphotransferase was not tissue-dependent but was dependent on the isomer of hydroxybiphenyl. The Km varied over a 500-fold range and the highest and lowest values of Km were found with p-hydroxybiphenyl and m-hydroxybiphenyl, respectively.