CHARACTERIZATION AND ISOLATION OF AN AGGLUTININ FROM SEMINAL PLASMA OF THE SEA-URCHIN

We investigated the biological features of a hemagglutinin present in seminal plasma of the sea urchin Paracentrotus lividus. The erythroagg lutinating activity restricted to rabbit erythrocytes is calcium-depen dent, relatively heat-stable, and strongly inhibited by the L(-) Confi guration of both arabinose and xylose. This hemagglutinin, purified by gel filtration and ion-exchange chromatography, was a single molecula r species of over 200 kDa. Experimental evidence suggests that the pre sent protein is not involved in the sperm-egg interaction or in the pr otection of semen from bacterial growth.