Purification and characterization of reversible sperm motility inhibitors from porcine seminal plasma.

Two sperm motility inhibitors (SMI1 and SMI2) were purified from porcine seminal plasma with high performance liquid chromatography (HPLC). Their molecular weights are about 15,000 as estimated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Both of them decreased the percentage of motile spermatozoa in a dose-dependent manner. The inhibitory effect can be abolished by addition of the porcine follicular fluid. Both SMI1 and SMI2 have similar amino acid composition, suggesting that they may be structurally related. They also have inhibitory effect on chymotrypsin.