D-fructose-binding proteins in bull seminal plasma: isolation and characterization

The heparin-binding activity of bull seminal plasma proteins was inhibited by D-fructose, D-glucose, inulin and glycogen; D-galactose, dextran and mannan had no effect. While the ejaculated sperm-heparin interaction was not influenced by the presence of saccharides, the heparin-binding activity of epididymal sperm was inhibited by D-fructose. The results of the binding studies were confirmed by affinity chromatography on immobilized heparin followed by elution with monosaccharides. Proteins adsorbed to a heparin-polyacrylamide column and eluted with D-fructose were analyzed by RP HPLC, SDS electrophoresis and by determination of the N-terminal amino-acid sequence. RNAase dimer, PDC-109 and metalloproteinase inhibitor (TIMP-2) were identified.