Tao Han, Wei Wanzhi, Mao Youan, Zhang Shufen, Xia Jianjun
State Key Laboratory of Chemo/Biological Sensing & Chemometrics, Hunan University, PR China.
Anal Sci. 2005 Sep;21(9):1057-61. doi: 10.2116/analsci.21.1057.
Piezoelectric quartz crystal impedance analysis technique was applied to study the chitosanolytic activity of pepsin. The method is based on the viscosity-density reduction of chitosan solution during the enzymatic degradation process. Experiments examined the time courses of the variations of motional resistance (deltaR1) for a quartz crystal. By comparing the deltaR1 response curves under different degradation conditions, the effects of pH, temperature, enzyme and substrate concentration on the chitosanolytic activity of pepsin was investigated in detail. The results suggest that the optimum pH and temperature were 4.6 and 55 degrees C, respectively. Increasing aptly the enzyme or substrate concentration was in favor of the degradation of chitosan. Moreover, the influence of the degree of deacetylation (DD) on the enzymatic degradation was studied. The result indicates that chitosan with a lower DD was easier to be degrade compared with chitosan with a higher DD. Also, it was found that there was a good linear relationship between the deltaR1 response and the DD value. The regression equation was deltaR1 = 0.058 x DD-6.795 and the correlation coefficient was 0.987.
采用压电石英晶体阻抗分析技术研究胃蛋白酶的壳聚糖分解活性。该方法基于酶促降解过程中壳聚糖溶液的粘度-密度降低。实验检测了石英晶体运动电阻（deltaR1）变化的时间进程。通过比较不同降解条件下的deltaR1响应曲线，详细研究了pH、温度、酶和底物浓度对胃蛋白酶壳聚糖分解活性的影响。结果表明，最佳pH和温度分别为4.6和55℃。适当提高酶或底物浓度有利于壳聚糖的降解。此外，研究了脱乙酰度（DD）对酶促降解的影响。结果表明，与高DD壳聚糖相比，低DD壳聚糖更容易降解。还发现deltaR1响应与DD值之间存在良好的线性关系。回归方程为deltaR1 = 0.058×DD - 6.795，相关系数为0.987。
