蜗牛酶降解部分乙酰化甲壳素的动力学

The kinetics of degradation of partially N-acetylated chitin by snail nut enzyme

使用蜗牛酶对水溶性部分脱乙酰化甲壳素进行降解，由粘度降低（△１／［η］）对时间的变化曲线确定降解反应初始速率，该降解曲线呈非线性，而用浓盐酸降解的曲线呈现较好的线性。随着甲壳素脱乙酰度的降低，酶降解反应速率迅速增加，表明乙酰基对蜗牛酶降解甲壳素起着重要作用。对蜗牛酶浓度和底物浓度对降解反应速率影响的研究表明该酶反应遵照Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｎ动力学。

Water-soluble chitins with degrees of deacetylation ranging from 60% to 98% were degraded with snail nut enzyme. Initial degradation rate (r) was detemined from plots of the viscosity decrease (△1/[η]) against time of degradation. The time courses of degradation of chitins with snail nut enzyme were non-linear, while the time courses of degradation of chitins with concentrated hydrochloric acid were linear. The initial degradation rates of chitin with snail nut enzyme increased evidently with increasing content in acetylated units, indicating that acetyl plays an important role in the degradation of chitin. The results from the effects of enzyme concentrations and substrate concentrations on the initial degradation rates showed that this snail nut enzyme-chitin system obeys Michaelis-Menten kinetics.