Polyacrylamide gel patterns of parotid saliva proteins in Caucasoids and Amerindians

Abstract

Parotid saliva protein samples collected from 69 Caucasoid and 71 Amerindian (Crow Indian Reservation, Montana) donors were subjected to polyacrylamide gel slab electrophoresis, pH 9.0. Coomassie Blue staining revealed a total of 36 distinguishable protein bands at equivalent positions on the gels from samples of both the Caucasoids and Amerindians. Marked variability of parotid protein patterns among both Caucasoids and Amerindians was evident. Seven bands were present in a significantly greater ( p < 0.05 − p < 0.005) proportion of Caucasoid samples, while one band was present in a significantly greater ( p < 0.005) proportion of Amerindian patterns. The average number of protein bands detected in the Amerindian patterns was significantly fewer ( p < 0.005) than that of Caucasoids. “Proline-rich” proteins were detected on additional gels of samples from both Caucasoids and Amerindians. Distinct variability among individuals from both groups was evident also in the occurrence of “proline-rich” parotid proteins. Reactions (bands) indicating “proline-rich” proteins were observed at 10 positions on gels from Caucasoid samples. Significantly fewer ( p < 0.005) “proline-rich” areas were detected on gels from Amerindian than Caucasoid saliva. Four of the “proline-rich” bands were present in a significantly greater ( p < 0.05 − p < 0.005) proportion of Caucasoid than Amerindian patterns. It is concluded that there are not consistent specific differences in parotid saliva protein composition between Caucasians and Amerindians. However, the proportion of subjects in which certain protein bands occur, following separation of the protein by polyacrylamide gel electrophoresis, differs between the two populations.