Biosynthesis of Heparin

This is the authors' abstract. We don't add key points for this paper.

Deacetylation of an N-acetylated glycosaminoglycan related to heparin is described in the presence of a microsomal preparation from mouse mast cell tumors. This N-deacetylation occurs when 3'-phosphoadenosine 5'-phosphosulfate is present during active glycosaminoglycan polymerization or when 3'-phosphoadenosine 5'-phosphosulfate is added subsequent to glycosaminoglycan polymerization. Loss of N-acetyl corresponds to 30 to 50% of the original N-acetylglucosamine moieties, and the product appears to be N-sulfated to the same degree as it is N-deacetylated. Thus the N-acetylated glycosaminoglycan previously described is shown to be a precursor for N-sulfated glycosaminoglycan indistinguishable from heparin. The reaction takes place in the presence of the same microsomal preparation that has previously been shown to catalyze glycosaminoglycan polymerization and sulfate incorporation, indicating a probable proximity of these reactions within the cell.