Possible amino acid repetitive sequences in the proline-rich glycoprotein of human parotid saliva

Abstract

The amino acid sequence of the proline-rich glycoprotein from human parotid saliva was studied using different preparations: native glycoprotein, tryptic glycopeptides, and their chemically deglycosylated homologous derivatives. The results indicate very similar structural features of the proline-rich glycoprotein and the tryptic glycopeptides and suggest that the peptide backbone of the glycoprotein comprises several repetitive domains containing one carbohydrate-peptide linkage and a proline-rich sequence. These data are in fair agreement with a preceding circular dichroism study (Aubert, J.P., Porchet, N., Boersma, A., Loucheux-Lefevbre, M.H. and Degand, P. (1982) Biochim. Biophys. Acta 704, 361-365).