Sulphogalactolipid sulphohydrolase activity of arylsulphatase purified from a marine gastropod Charonia lampas

Abstract

Sulphatide, cerebroside 3-sulphate, was hydrolyzed at a considerable rate by arylsulphatase (aryl-sulphate sulphohydrolase, EC 3.1.6.1) purified from a marine gastropod, Charonia lampas. However, it was scarcely hydrolyzed by glycosulphatase (sugar-sulphate sulphohydrolase, EC 3.1.6.3) from the same origin. The same was observed with seminolipid, a sulphoglycerogalactolipid. The enzymatic characteristics of both sulphogalactolipid and sulphohydrolase activities of the arylsulphatase were determined as follows. The enzyme activities are stimulated by the addition of sodium taurodeoxycholate and MnCl 2. The pH optimum of sulphatide sulphohydrolase activity was pH 5.0, while seminolipid sulphohydrolase activity had maximum activity at pH 5.5. Both of these pH versus activity curves were broad. The K m value was 6.22 · 10 −5 M for both substrates. However, the V values with sulphatide were lower by a factor of one-third than those with seminolipid. These enzyme activities were inhibited by substrates of the arylsulphatase, i.e., p- nitrophenyl sulphate, p- nitrocatechol sulphate, ascorbate 2-sulphate and each other sulphogalactolipid, but not by glucose 6-sulphate. Sulphate and phosphate anions inhibited both of the enzyme activities.