Canine sulfotransferase SULT1A1: molecular cloning, expression, and characterization

Sulfotransferases (SULTs) are involved in detoxification and activation of various endogenous and exogenous compounds including important drugs and hormones. SULT1A, the phenol-SULT subfamily, is the most prominent subfamily in xenobiotic metabolism and has been found in several species, e.g., human, rat, and mouse. We have cloned a phenol-sulfating phenol SULT from dog (cSULT1A1) and expressed it in Escherichia coli for characterization. cSULT1A1 showed 85.8, 82.7, 76.3, and 73.6% identities to human P-PST, human M-PST, rat PST-1, and mouse STp1, respectively. It consists of 295 amino acids, which is in agreement with the human ortholog and sulfate substrates typical for the SULT1A family, i.e., p-nitrophenol (PNP), α-naphthol, and dopamine. The Km for PNP was found to be within the nanomolar range. It also sulfates minoxidil and β-estradiol but not dehydroepiandrosterone. Western blot analysis indicated that this newly cloned enzyme was found to be ubiquitously expressed in canine tissues with highest expression in male and female liver.