Posttranslational Modifications of Lysozyme

在酵母基因修饰表达系统中，研究了糖基化和脂质化等翻译后修饰对蛋清溶菌酶功能特性的影响。n链糖基化信号（Asn-X-Thr/Ser）通过定点诱变在第19位和第49位构建。所制得的多甘露溶菌酶在提高热稳定性、乳化性和降低致敏性方面效果显著。虽然通过n -肉豆荚化信号序列附着在n端来检测溶菌酶的脂化，但溶菌酶的折叠不能产生展开形式。与肉豆蔻酸长度相同的疏水肽不是亲脂作用，而是附着在溶菌酶的c端。疏水附着溶菌酶（H5）对革兰氏阴性菌具有较强的抑菌活性。将这些改性的溶菌酶插入烟草中，以提高其抑菌作用。转基因烟草对灰霉病表现出较强的抗性。

Effects of post-translational modification such as glycosylation and lipophilization on the functional properties of hen egg white lysozyme were investigated in yeast expression system using genetic modification. The N-linked glycosylation signal (Asn-X-Thr/Ser) was constructed in the position 19 and 49 by site-directed mutagenesis. The polymannosy lysozyme thus obtained was very effective to enhance the thermal stability and the emulsifying property and to decrease the allergenicity. Although the lipophization of lysozyme was examined by the attachment of N-myristylation signal sequence into N-terminal, the folding of lysozyme failed to produce the unfolded form. Instesd of lipophilization, the hydrophobic peptide having the same length as myristic acid was attached to C-terminal of lysozyme. The hydrophobic attached lysozyme (H5) revealed a strong antimicrobial activity agianst Gram-negative bacteria. These modified lysozymes were inserted into tobacco to improve the bactericial action. The transgenic tobacco showed a strong resistance to gray mold.