Boar, bull, ram and rabbit seminal plasma proteins were studied by gel disc electrophoresis at pH 4·5 and 8·6 and by isoelectric focusing on plates using ampholines of pH range 3 to 10.
The number of proteins identified in the seminal plasma of the four species using gel disc electrophoresis was greater than had been found in most previous reports, more being identified in ram and rabbit than in boar and bull seminal plasma. Bovine plasma albumin and γ-globulin each appeared as a number of protein bands.
Due to the better resolution, the number of proteins found in the same seminal plasma samples using isoelectric focusing was greater than that obtained with gel disc electrophoresis.
Boar seminal plasma proteins were found to be basic in character. Those of the other animals possessed acidic, neutral and basic isoelectric points. This was more effectively demonstrated by the isoelectric focusing technique. The bovine plasma albumin and γ-globulin appeared on the plates as groups of eight and twelve to fourteen components, respectively. Their similarity to the seminal plasma proteins was very small.
The protein pattern obtained on the ampholine plate was affected by the site of sample application along the pH gradient. This was more clearly shown when the pH gradient was established before a sample was placed on the plate. Possible explanations for these alterations are discussed.