Human platelet arylsulphatases: identification and capacity to destroy SRS-A

Arylsulphatases IIA and IIB have been separately identified in human platelets by use of anion exchange chromatography and gel filtration. Arylsulphatase IIA had a molecular weight of 160,000 and a pH optimum of 4.5. Arylsulphatase IIB had a molecular weight of 60,000 and a pH optimum of 5.5. Both arylsulphatases IIA and IIB were inhibited by phosphate and sulphate ions characteristic of this enzyme class. Platelets, upon exposure to ionophore A-23187 or thrombin, discharged arylsulphatase coincident with beta-glcuronidase release. Partially purified platelet arylsulphatase IIB inactivated rat SRS-A.