Basic Salivary Proline Rich Protein 3 (PRB3)

Basic salivary proline-rich protein 3 is a proline-rich salivary protein. It is a major constituent of parotid saliva. This protein is proposed to act as a bacterial receptor. This gene and five other genes that also encode salivary proline-rich proteins (PRPs), as well as a gene encoding a lacrimal gland PRP, form a PRP gene cluster in the chromosomal 12p13 region.The G1-8 protein variant was found in Ashkenazi Jews with a gene frequency of approximately 0.008 but was not found in the general Caucasian, black, or Japanese populations. Both G1-8, coded by the PRB3 locus, and Pa-1, coded by the PRH1 locus, are disulfide bonded and probably modify salivary peroxidase (part of an important intraoral antibacterial system) through formation of disulfide-bonded heterodimers.