A new arylsulfatase (EC 3.1.6.1) was isolated from the liver of the marine mollusk Turbo chrysostomus. The enzyme catalyzed hydrolysis of potassium p-nitrophenylsulfate, did not affect natural fucoidan, and catalyzed cleavage of sulphate in the C4 position of xylose included in carbohydrate chains of holothurian triterpene glycosides. Halistanol sulphate and glycosides from starfish that contained sulfates in the aglycon part of the molecule inhibited the activity of the arylsulfatase. Several holothurian glycosides in small concentrations (3.5-8 x 10(-10) M) increased the enzyme activity. The arylsulfatase activity was maximal at pH 7. Its molecular weight was 35 kDa according to gel-filtration. The Michaelis constant (K-M) for hydrolysis of p-nitrophenylsulfate was 10 mM. The inactivation half-life of the enzyme was 15 min at 55A degrees C.