Complete amino-acid sequence of the naturally occurring A2 activator protein for enzymic sphingomyelin degradation: identity to the sulfatide activator protein (SAP-1)

The naturally occurring A2 activator protein for enzymic sphingolipid degradation is characterized by complete amino-acid sequence and carbohydrate content. It consists of 79 amino-acid residues and has a molecular mass of 8.875 kDa. The polypeptide chain contains 2 mol of N-acetylglucosamine, bound to asparagine in position 21, as well as 2 mol of galactose and mannose per mol protein. The primary structure of the A2 activator protein is identical to that of the sulfatide activator protein (SAP-1). Possible differences in the carbohydrate content are discussed.