Immunochemical characterization of developmental changes in rat hepatic hydroxysteroid sulfotransferase. |
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Authors: | H Homma I Nakagome M Kamakura M Matsui |
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Institution: | Kyoritsu College of Pharmacy, Tokyo, Japan. |
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Abstract: | A major isoenzyme of hepatic androsterone-sulfating sulfotransferase (AD-ST) was purified from adult female rats. The activity was purified 122-fold over that found in the cytosol and showed a single protein band with a subunit molecular mass of 30 kDa after sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified enzyme exhibited four isoelectric variants of subunits on denaturing isoelectrofocusing gels (pI = 5.8, 6.1, 6.7 and 7.2). Rabbit antiserum raised against the enzyme specifically detected AD-ST polypeptide in rat liver cytosol. Immunoblot analysis of liver cytosol from female and male rats at various ages showed good correlation between the levels of AD-ST activity and AD-ST polypeptide. Significant levels of AD-ST activity and polypeptide were detected in senescent male rats, though normal adult male rats have very low levels of AD-ST activity and protein. The relative content of the isoelectric variants of AD-ST were different in liver cytosol of weanling and adult females, indicating that age- and gender-related alterations of hepatic AD-ST activity are primarily determined by the levels of AD-ST polypeptide and the relative amounts of the four isoelectric variants of the enzyme. |
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