化学法改性溶菌酶抑菌性及其结构研究

Study on antimicrobial properties and structure of chemical modified lysozyme

采用化学法改性溶菌酶,以EDAC作为缩合剂,肉桂酸、咖啡酸和对香豆酸作为改性剂,形成一定程度的改性酶,并对改性酶的抑菌性及结构进行研究。结果表明:与天然酶相比,改性酶的活力有所下降,但是对革兰氏阴性菌的抑制作用增强,咖啡酸改性酶和对香豆酸改性酶对大肠杆菌和铜绿假单胞菌的最小抑菌浓度均为0.5 mg/mL,肉桂酸改性酶为0.75 mg/mL,但对革兰氏阳性菌的抑菌能力有所降低,咖啡酸改性酶和对香豆酸改性酶对金黄色葡萄球菌和溶壁微球菌的最小抑菌浓度均为1.25 mg/mL,肉桂酸改性酶对二者的最小抑菌浓度分别为1.25 mg/mL和1.50 mg/mL,3种改性酶的各二级结构含量均发生一定的变化。

The method of chemical modification was used to modify lysozyme in this study. With EDAC as con- densing agent, cinnamic acid, caffeic acid and p-coumaric acid as modifier, a certain degree of modified enzyme was formed. The properties of the modified enzymes were studied. Results showed that the lytic activity of modified en- zyme declined slightly, but the modified enzyme expanded the bactericidal spectrum to the Escherichia coli and Pseud- omonas aeruginosa. The minimal inhibition concentrations of caffeic acid and p-coumaric acid modified enzyme were both 0.5 mg/mL, and that of cinnamic acid modified enzyme was 0.75 mg/mL. However, the efficacy for Staphylo- coccus aureus and Micrococcus lysodeikticus was reduced slightly, the minimal inhibition concentrations of caffeic acid and p-coumaric acid modified enzyme for themwere both 1.25 mg/mL, and that of cinnamic acid modified enzyme was 1.25 mg/mL and 1.50 mg/mL, The secondary structures of these three modified enzymes had some changes.