Immunological cross-reactivity and sequence homology between salivary proline-rich proteins in human and macaque monkey ( Macaca fascicularis) parotid saliva

Abstract

A proline-rich protein (PRP) isolated from parotid saliva of a macaque was compared with the major human salivary anionic PRP. The amino acid composition of the macaque PRP also had a high proline value of 234 residues/1000 and lacked cysteine, methionine, tyrosine and tryptophan. Antiserum to a major human PRP showed immunological cross-reactivity with the macaque PRP. The origin of the salivary PRPs from a common ancestral gene was suggested by automatic sequence analysis. Alignment of the N-terminal serine with residue 3 of human PRPs showed that at least 23 of the first 40 residues were identical.