title: A 225 K dalton glycoprotein is the active core structure of the sperm-binding factor of the sea urchin, Anthocidaris crassispina.
abstract: Fab fragments against 225 000 D glycoprotein (225 K), 87 000 D protein (87K) 80 000 D glycoprotein (80 K) of partially purified sperm-binding factor of Anthocidaris crassispina were prepared, and their effects upon fertilizability of dejellied homologous and heterologous eggs examined. Only the 225 K Fab impaired the fertilizability of homologous, not heterologous eggs by decreasing their sperm-binding capacity. It was concluded that 225 K glycoprotein is the active core structure of the sperm-binding factor of this species. The possible participation of the other two proteins as residual ingredients of the sperm-binding factor was also discussed. Immunofluorescence studies showed that 225 K core protein is localized on the whole surface of unfertilized eggs and of fully-grown oocytes. The fluorescence disappeared following fertilization.
mesh_terms: D000818:Animals; D005260:Female; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000032:analysis* / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D010063:Ovum / Q000032:analysis*; D011485:Protein Binding; D012617:Sea Urchins / Q000032:analysis*; D013094:Spermatozoa / Q000378:metabolism*; D015053:Zygote / Q000032:analysis
chemical_list: D006023:Glycoproteins