Genetic studies on pancreatic proteinase in Japanese quail

A genetic variation was found in pancreatic proteinase of Japanese quail. In eight bands of proteinase isozymes, the variation of band 5 (presence or absence) was detected among quails. Band 5 was identified as a chymotrypsin. The presence and absence of band 5 are controlled by a pair of allelic genes (Prt-5A and Prt-5a) on an autosomal locus, and gene Prt-5A, causing expression of band 5, is dominant to gene Prt-5a, a null allele for band 5. Zymograms of proteinases and their zymogens were also compared; no variation of chymotrypsinogen; corresponding to chymotrypsin Prt 5 were detected. It is suggested that the Prt-5 variant of chymotrypsin may be formed during activation of chymotrypsinogen.