Chemistry Department, University of Winnipeg, Winnipeg, Manitoba R3B2E9, Canada.
Protein J. 2010 Aug;29(6):398-406. doi: 10.1007/s10930-010-9266-0.
Single enzyme molecule assays were performed using capillary electrophoresis-based protocols on beta-galactosidase from Lactobacillus delbrueckii, Lactobacillus reuteri, Lactobacillus helveticus and Bacillus circulans. The enzyme was found to show static heterogeneity with respect to catalytic rate and the variance in rate increased with protein size. This is consistent with the proposal that random errors in translation may be an important underlying component of enzyme heterogeneity. Additionally these enzymes were found to show static heterogeneity with respect to electrophoretic mobility. Comparison of wild-type and rpsL E. coli beta-galactosidase expressed in the presence and absence of streptomycin suggested that increases in error do not result in detectable increases in the dynamic heterogeneity of activity with increasing temperature. Finally, a method was developed to measure the dynamic heterogeneity in electrophoretic mobility.
使用基于毛细管电泳的方案对德氏乳杆菌、罗伊氏乳杆菌、瑞士乳杆菌和环状芽孢杆菌的β-半乳糖苷酶进行单酶分子分析。发现该酶在催化速率方面表现出静态异质性，并且速率的变化随着蛋白质大小的增加而增加。这与翻译过程中的随机错误可能是酶异质性的一个重要潜在组成部分的观点一致。此外，这些酶在电泳迁移率方面也表现出静态异质性。比较在有无链霉素存在的情况下表达的野生型和 rpsL 大肠杆菌β-半乳糖苷酶表明，错误的增加不会导致随着温度的升高，活性的动态异质性可检测到增加。最后，开发了一种测量电泳迁移率动态异质性的方法。
