Basic Salivary Proline Rich Protein 2 (PRB2)

The Ps proteins of saliva are so called because they are parotid size variants, i.e., variants in the size of parotid salivary protein. The polymorphism is determined by 1 unexpressed and 2 expressed alleles at an autosomal locus. The electrophoretic polymorphism is manifested by apparent differences in molecular weights between the Ps proteins which are glycosylated. Ps and Pm are closely linked to Pr, Pa, Db, and G1. Goodman and Karn (1983) presented evidence supporting the conclusion of Azen and Denniston (1980) that there is a molecular weight difference between the 2 allelic proteins Ps-1 and Ps-2. The difference appears to be due to an extension of the Ps-2 chain (presumably at its COOH-end). Minaguchi et al. (1988) described new variants.