Enhancement of Transglycosylation Activity of Lysozyme by Chemical Modification

An attempt to enhance the transglycosylation activity of lysozyme -'as made by chemical modification. Computer simulation of the Iysozyme-catalyzed reaction indicated that inhibition of the sugar residue binding te the binding subsite A caused a significant increase in transglycosylation activity. Therefore, the binary modification of Asp 1O1 and Trp 62 in hen egg white lysezyme was made in order to inhibit he sugar residue binding to subsite A. The modified lysozyme, in which the aMnity of the sugar residue to sllbsite A was decreased b}' about 2kcal/mol of binding free energy change, increased the amounts of transgl)'cosylatio" products in comparison with the native lysezyme. In particular, the octamer of ,N-acetylglucosamine was abundantly produced from the initial substrate, pentamer. The modified tysozyme should be usefu1 t'or synthesis of oligesaccharides with a high degree ef polymerization.