Enzymatic sulfation of cholesterol by rat gastric mucosa

A sulfotransferase which catalyzes transfer of the sulfate group from 3'-phosphoadenosine-5'phosphosulfate to cholesterol has been demonstrated in the rat gastric mucosa. The product of the reaction was characterized as cholesterol sulfate by two-dimensional thin-layer Chromatographic behavior, and gas-liquid chromatography of cholesterol after acid solvolysis. The bulk of enzyme activity was found in the cytosol fraction. Sulfation of cholesterol did not require added Mg +2, Mn +2, or Ca +2, and was unaffected by ethylenedia-minetetraacetate. Triton X-100 moderately enhanced the enzyme activity. A broad pH optimum from pH 6.0–9.0 was exhibited with a maximum at pH 7.0–7.5. The apparent Km for PAPS was 0.8 × 10 −6M. The possible function of cholesterol sulfate in gastric mucosa is discussed.