Zone Electrophoresis of Human Parotid Saliva in Acrylamide Gel

Abstract

THE zone electrophoresis of human parotid saliva proteins has been carried out with a variety of supporting media, including filter paper, cellulose acetate, agar gel and starch gel, with separations usually of from five to twelve fractions^1–8. In a comparative investigation of these media, D'Silva and Ferguson⁷ obtained their most satisfactory results with a combination of cellulose acetate and starch gel, thereby separating seventeen protein components from the parotid saliva of one subject. The present report concerns an examination of acrylamide gel as another medium for the zone electrophoresis of parotid saliva proteins. Preliminary experiments with acrylamide-gel strips have yielded protein patterns in which twenty or more fractions could be visually distinguished when the electrophoresis was carried out in 0.1 M tris-EDTA–boric acid buffer at pH. 9.0. The tests were conducted on individual collections of parotid saliva from three subjects and on pooled collections of parotid saliva from several subjects. Fig. 1 shows the electrophoresis pattern of a sample of the pooled parotid saliva. Under the conditions of the experiment, more than half the staining components migrated anodically with generally better resolution than is evident for the cathodically-migrating components. Although disk electrophoresis on acrylamide gel has been widely used in investigations of serum proteins, gel strips were used for this investigation of parotid saliva in order to obtain the complete pattern of staining components, migrating both anodically and cathodically, for each electrophoresis run. Gel strips also permit the handling of larger quantities of protein than is feasible with disk electrophoresis, should recovery of particular fractions be desired. Salivary amylase, a troublesome factor in the starch-gel electrophoresis of saliva proteins, does not attack acrylamide gel.