The amino acid sequence of monal pheasant lysozyme and its activity

The amino acid sequence of monal pheasant lysozyme and its activity were analyzed. Carboxymethylated lysozyme was digested with trypsin and the resulting peptides were sequenced. The established amino acid sequence had one amino acid substitution at position 102 (Arg to Gly) comparing with Indian peafowl lysozyme and four amino acid substitutions at positions 3 (Phe to Tyr), 15 (His to Leu), 41 (Gln to His), and 121 (Gln to His) with chicken lysozyme. Analysis of the time-courses of reaction using N-acetylglucosamine pentamer as a substrate showed a difference of binding free energy change(- 0.4 kcal/mol) at subsites A between monal pheasant and Indian peafowl lysozyme. This was assumed to be caused by the amino acid substitution at subsite A with loss of a positive charge at position 102 (Arg102 to Gly).