Genetic Control of Salivary Protein Composition

¹ Division of Dental Research, Faculty of Dentistry, and Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada

The proteins of human parotid and extraparotid saliva have been studied by means of electrophoresis in starch-urea-formate gels at pH 3.7. Parotid and extraparotid protein patterns showed as many as 17 and 18 different protein zones, respectively. It was found that reproducible salivary patterns could be obtained for most individuals provided the first 3 ml. of each stimulated secretion was rejected. Several extraparotid protein zones were poorly reproducible despite this precaution.

Parotid and extraparotid salivary patterns for different individuals showed frequent similarities in the number of protein zones but marked differences in their relative concentration. The parotid and extraparotid protein patterns were similar for both members in two of 30 random pairs of unrelated children, in four of 34 pairs of fraternal twins and in ten of 16 pairs of identical twins. It is concluded that the relative concentration of many proteins in both secretions is under strong genetic control.