Coagulation Proteins in the Seminal Vesicle and Coagulating Gland of the Mouse1

As part of a program to study the formation of the vaginal plug in the mouse, we estimated the number of proteins taking part in the coagulation process, using two electrophoretic methods. Acid polyacrylamide disc gel electrophoresis (pH 4.3) gave 11 basic seminal vesicle protein bands, of which 7 disappeared from the supernatant following coagulation in vitro. Polyacrylamide gel isofocusing on the other hand gave a pattern of 25 protein bands, of which 5 disappeared from the supernatant following coagulation in vitro. The 5 bands focused within the pH range 8.2 to 9.3 and corresponded to the 7 bands removed by coagulation in the acid gel system. The data thus suggest that as many as 5, and perhaps 7, soluble proteins may take part in coagulation. The principal band in both systems focused in the pH 9.3 region and had a molecular weight of 43,000 estimated by SDS gel electrophoresis. We found no genetic variation in electrophoretic pattern of basic fraction proteins among mice of the 16 inbred strains and three translocation stocks examined. Acid gel electrophoresis of rat seminal vesicle gland (SVG) secretion, before and after coagulation in vitro, gave patterns similar to those of the mouse. Seven of eleven bands having Rf values like those of the mouse disappeared following in vitro coagulation. Rat and mouse heterologous coagulating gland-seminal vesicle gland (CG-SVG) coagulation mixtures gave similar patterns.