Catalytic Mechanism of Lysozyme Based on the Structures of Invertebrate-type Lysozyme and Chicken-type Lysozyme

Abstract

Based on the structure of invertebrate-type lyzozyme, Venerupis philippinarum lysozyme (VpL), we designed Asn46Asp/Asp52Ser or Asn46Glu/Asp52Ser hen egg white lysozyme (HEWL) mutants. Both lysozyme mutants possessed lysozyme acitivity like VpL and HEWL. Although Asn46Glu/Asp52Ser mutant formed a glycosyl adduct in the reaction with the N-acetylglucosamine oligomer, however, the turnover rate of estimated from the glycosyl formation and decomposition rates was only 20% of the observed hydrolysis rate of the substrate. From these results, we discussed the catalytic mechanism of lysozymes.