DETECTION OF A GLYCOSYLATED FORM OF HEN EGG-WHITE LYSOZYME

By assaying lysozyme activity after denaturing polyacrylamide gel electrophoresis of commercial hen egg white lysozyme preparations, minor lysozymal activity was detected as an 18-kDa protein. After electrophoretic purification for microsequencing, the N-terminus sequence of the 18-kDa lysozyme was found to be identical with mature 14.4-kDa hen egg white lysozyme. The 18-kDa hen egg white lysozyme was judged to be glycosylated based on a 3.6-kDa decrease in molecular mass after N-glycosidase F treatment, binding to concanavalin A - Sepharose, and staining with periodate - Schiff's reagent. The minor form corresponded to about 0.3% of lyzozyme molecules.