Isolation and characterization of specific rat epididymal proteins.

The partial purification and characterization of specific rat epididymal proteins (SEP) is reported. Starting from the cytosol fraction obtained from epididymal homogenates, protein C was purified 15-fold and proteins D--E were purified 19-fold. The molecular weight, determined by molecular sieving, of protein C was 22,400 while that of D--E was 37,000. These proteins stained as glycoproteins with periodic acid--Schiff reagent. The isoelectric point of protein D was 5.13 while that of protein E was 4.95. Protein C separated into 3 bands during isoelectric focussing. The major component focussed at 5.56 and the two minor components at pH 5.38 And 5.79. Using a specific antiserum we could confirm the organ specificity of SEP and their androgen-dependence.