Examination of human tissue cytosols for expression of sulfotransferase isoform 1A2 (SULT1A2) using a SULT1A2-specific antibody.

Sulfotransferase isoform 1A2 (SULT1A2) is a member of the cytosolic sulfotransferase family of phase II detoxification enzymes. Studies with recombinant enzymes have shown that SULT1A2 can catalyze the bioactivation of several procarcinogens, indicating a potential role in chemical carcinogenesis. However, previous studies have suggested that the SULT1A2 transcript has a splicing defect that might prevent it from becoming translated into protein; therefore, we sought to determine the expression of SULT1A2 in tissues. An antibody directed against a region of human SULT1A2 that differs from other known sulfotransferase isoforms was developed and used to screen a large number of cytosolic fractions from various tissues. Although the SULT1A2 antibody recognized recombinant SULT1A2 and did not cross-react with other SULT isoforms, the expression of SULT1A2 was not detected in any tissue examined. These studies suggest that if SULT1A2 is expressed as protein, the levels are very low and that SULT1A2 probably does not play a physiological role in chemical carcinogenesis.