Sulfation of N-desulfoheparin and heparan sulfate by a purified enzyme from mastocytoma

Abstract

3'-Phosphoadenylylsulfate:N-desulfoheparin sulfotransferase from a postmicrosomal particulate fraction of Furth mouse mast cell tumor was solubilized by snake venom phospholipase and purified further by DEAE-cellulose chromatography. The purified enzyme was free of endogenous sulfate acceptor and 3'-phosphoadenylylsulfate sulfohydrolase activity. The sulfotransferase catalyzed sulfate transfer from 3'-phosphoadenylylsulfate-³⁵S not only to N-desulfoheparin, but also to heparan sulfate, dermatan sulfate, and a glycosaminoglycan prepared from mast cell tumor. Heparin, chondroitin-4-sulfate, and mixed isomers of chondroitin sulfate from cartilage were practically inactive. The reaction products of N-desulfoheparin and heparan sulfate were found to be primarily N-sulfated. Sulfation of heparan sulfate was more rapid and more extensive than that of N-desulfoheparin, although the former contained fewer free amino groups. Synthetic N-acetylheparin and N-succinylheparin exhibited only very low sulfate-accepting ability. Apparently free amino groups are required for the enzymatic N-sulfation of glycosaminoglycans and some special structural features facilitate sulfate transfer to the amino groups of heparan sulfate.