Lytic activity and biochemical properties of lysozyme in the coelomic fluid of the sea urchin Strongylocentrotus intermedius

Lysozyme was identified in the coelomic fluid including coelomocytes of the sea urchin Strongylocentrotus intermedius, and its lytic activity and biochemical properties were examined in this study. The urchin lysozyme was electrophoretically fractionated to a single lytic band of about 14 kDa. No distinct difference in the lytic activity of this enzyme was found between urchins held at two temperatures, 11 degrees and 25 degrees C. The lysozyme of this species was purified through several procedures: salting out with ammonium sulfate, precipitation by ethanol saturation, gel filtration with a Biogel column, and an affinity chromatography with a heparin Sepharose column. The combination method of Biogel filtration and affinity chromatography resulted in the most purified lysozyme fraction, but we could not obtain a single protein band in SDS-PAGE. In addition, anti-hen egg white lysozyme (HEWL) antibody was produced and confirmed to react specifically with the urchin lysozyme in this study. Therefore, the HEWL antibody may be available for examining the lytic activity of lysozyme at an individual level to determine the biodefense activity of sea urchins. (C) 1999 Academic Press.