Occurrence of lysozyme in the eggs of coho salmon Oncorhynchus kisutch

Abstract

The occurrence of lysozyme in the eggs of coho salmon Oncorhynchus kisutch is reported for the first time. The eggs were shown to contain high levels of the enzyme, the concentration In the yolk being 1900 pg ml-l. Purification of the enzyme was achieved using chitin-coated cellulose and gel filtration. Only one active molecule was isolated and it was shown by SDS-PAGE to have a molecular weight of 14.5 kD. Similar levels of lysozyme were found in the eggs of 2 other species of salmonids also tested. The significance of the egg yolk lysozyme is dscussed with respect to its role as a natural defence factor against microorganisms, particularly bacteria.