SEPARATION AND IDENTIFICATION OF SOME OF PROTEIN COMPONENTS OF RAT PAROTID SALIVA

Rat parotid saliva was collected from cannulated glands of adult, male, Sprague-Dawley rats and analyzed by means of polyacrylamide gel disc electrophoresis coupled with specific enzyme tests for amylase, DNase, and RNase. Twelve to thirteen bands of protein were seen in the anionic gels, and nine were seen in the cationic gels. Four of the bands in the anionic gels showed amylase activity when tested on starch-substrate slides. The quantitative distribution of amylase activity among these four isozyme bands of isoproterenol-evoked saliva was shown to change if this saliva exposed to room temperature in the undiluted state. This shift in isoamylases was not influenced by dilution at different ionic strengths, and persisted even when the amylase was isolated from the saliva. The shift was not reversed by cooling in either the undiluted or diluted state. DNase and RNase activities were located in the gels. The DNase could be seen in both the anionic and cationic gels whereas the RNase migrated only in the cationic system. These activities were clearly separate and no cross-reactivity was seen. © 1969.