Studies on rat hepatic hydroxysteroid sulfotransferase--immunochemistry, development and pI variants

Rat hepatic hydroxysteroid sulfotransferase with sulfoconjugates androsterone (androsterone-sulfating sulfotransferase) is an oligomer consisting of several subunits with distinct pI values but with the same molecular mass (pI variants). N-terminal amino acid sequences of the pI variants are all identical. The enzyme is exclusively present in the liver, in which its lobular localization is sex-dependent. The localization of the enzyme is markedly different from that of an isoenzyme of phenol sulfotransferase. In weanling and adult female rats, the relative abundance of the pI variants is different. During development from weanling stage to adulthood, the amounts of acidic variants increase, whereas the relative levels of alkaline variants remain constant.