The protein spectrum of boar seminal plasma is formed mainly by the seminal vesicle fluid proteins, and to a lesser extent by the proteins in the fluids of the cauda epididymidis and prostate.
The proteins of the seminal plasma, the fluids of the cauda epididymidis, prostate, seminal vesicles and the blood serum were divided into five peaks by column chromatography on Sephadex G-100. The proteins of Peak I in boar seminal plasma (mol. wt at least 150,000) were mostly derived from the seminal vesicle fluid and to a small extent from the fluids of the cauda epididymidis and prostate. The proteins of Peak II (mol. wt 120,000) were found in the blood serum only, and those of Peak III (mol. wt 69,000) in the seminal vesicle fluid, the fluid of the cauda epididymidis and the prostate. Peak IV (mol. wt 34,000) was formed by proteins originating mainly from the seminal vesicles and partly from the prostate. The proteins of Peak V (mol. wt 12,000 to 14,000) were derived from the fluids of the cauda epididymidis and the prostate.
These conclusions were confirmed by comparing the activity of acid and alkaline phosphatase and esterase by means of disc electrophoresis on polyacrylamide gel at pH 9·4 and 4·3 and by immunoelectrophoresis of all the fluids and fractions obtained by column chromatography of proteins on Sephadex G-100.