THE RELEASE OF LYSOSOMAL ARYLSULFATASE FROM LIVER LYSOSOMES EXPOSED TO 2-CHLOROETHYLETHYL SULFIDE

Treatment of a lysosome-rich fraction from liver with 2-chloroethyleth yl sulfide resulted in a dose-dependent release of arylsulfatase, The inclusion of Ca2+ enhanced the enzyme release by approximately 2.3-fol d, The enhancing effect of Ca2+, showing an EC(50) value of 30 mM, was mimicked by neither Mg2+ nor Mn2+. Studies on a structural requiremen t and a time-dependent release suggest that the Ca2+-dependent release proceeds via a specific process involving the alkylation of lysosomal membranes by 2-chloroethylethyl sulfide. Furthermore, the Ca2+-depend ent process was prevented partially by either leupeptin or gentamycin, but neither pepstatin nor PMSF, implying that the enzyme release may be partially mediated by lysosomal cysteine-protease or phospholipase. Meanwhile, the Ca2+-independent release seems to be expressed non-spe cifically by various compounds.