Purification And Characterization Of A Lysozyme From The Intestine Of Sea Cucumbers

Lysozyme, also called cell wall hydrolase, specially function to peptidoglycan, chainmaterial of cell wall, exists in many tissues and secretion for animal, plant, protozoa, insect aswell as microorganism. Lysozyme is a kind of protein, has been widely used in food,medicine and biology for its safety. The commercial lysozyme, mainly obtained from hen eggwhite, only function to gram positive bacteria, so its applied field was limited. In recent yearsthe research to lysozyme from many source have been done widely, but the report of researchto lysozyme from marine life was very little. In this the research to purification andphysico-chemical properties of a new marine life lysozyme had been done, made a foundationto further research and application to marine life lysozyme.A lysozyme from the intestine of sea cucumbers was purified through the Cloud PointExtraction (CPE), cation-exchange chromatography with CM52cellulose and gel filtrationchromatography with Sephadex G-75.The result show that, cation-exchange chromatography with CM52cellulose had aevident effect to purification of lysozyme, and purification fold was11.3. The purificationfold of lysozyme through gel filtration chromatography with Sephadex G-75after CM52was18.7. Finally, the specific activity, purification fold and yield of lysozyme were3026.1U/mg,18.7and46%, respectively.The final enzyme preparation was nearly homogeneous in SDS-PAGE and its molecularweight was estimated as approximately16kD. The optimum pH and temperature againstMicrococcus lysodleikticus were pH6.5and35℃, respectively, and the enzyme was stable attemperature below45℃and pH4.0～8.0. The purified lysozyme has showed broad-spectrumagainst many bacteria, not only inhibiting the growth of Gram-positive bacteria, but also andGram-negative bacteria as well as a number of pathogens.