Isolation and characterisation of glycopeptides from digests of human Tamm-Horsfall glycoprotein.

Glycopeptides were isolated from pronase digests of human Tamm-Horsfall glycoprotein and its asialo derivative. The carbohydrate moiety of the major glycopeptide preparation isolated from the former digests had an apparent molecular weight of 4300, and those of two glycopeptides isolated from the latter digests had molecular weights of 3600 and 2300. These data, together with the compositions of the glycopeptides, indicate that the Tamm-Horsfall glycoprotein has at least five asparagine residues substituted by complex carbohydrate moieties, three being of one type, relatively rich in galactose, and two containing more sialic acid but less galactose. A small amount of a mannose-rich glycopeptide was also recovered from the digests of the Tamm-Horsfall glycoprotein.