Enzymatic sulfation of triglucosyl monoalkylmonoacylglycerol in rat salivary glands.

A sulfotransferase activity present in the cytosol fraction of rat submandibular and parotid salivary glands catalyzes the transfer of sulfate group from 3'-phosphoadenosine-5'-phosphosulfate to C-6 of the terminal glucose residue of Glc alpha 1 leads to 6Glc alpha 1 leads to 6Glc alpha 1 leads to 3-1, (3)-0-alkyl-2-0-acylglycerol to form sulfated triglucosyl glyceroglucolipid. The reaction proceeds at its optimum at pH 7.8, and requires the detergent Triton X-100, F1- and Mg2+. The enzyme does not catalyze the sulfation of glycosphingolipids. The apparent Km of the submandibular enzyme for triglucosyl glyceroglucolipid is 78.4 microM, and that of parotid, 58.8 microM. Analysis of the permethylated 35S-labeled enzymatic product demonstrated that the sulfate group is located at C-6 of the terminal glucose residue.