Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5512224 | International Journal of Biological Macromolecules | 2017 | 6 Pages |
Single molecule assays were performed on the enzyme E. coli β-glucuronidase using a capillary electrophoresis-based protocol. Electrophoretic mobility, catalytic rate and activation energy of catalysis were all found to be heterogeneous. The average mobility at 22 °C was â1.1 Ã 10â8 ± 0.1 m2Vâ1 sâ1 (N = 49) with a total range of â0.6 to â1.3 Ã 10â8 m2Vâ1 sâ1. The range in electrophoretic mobility suggests that the differences in shape or charge of the individual molecules underlying the heterogeneity are likely minimal. The average catalytic rate at 22 °C was 37,000 ± 19,000 minâ1 (N = 49) with a total range of 14,000 to 130,000 minâ1. Both of these properties were measured simultaneously for each of the molecules. There was a weak correlation (r2 = 0.43) between mobility and rate with the molecules with a less negative mobility having a tendency to have a higher rate. The average activation energy of catalysis, as determined by comparing rates at 22 and 35 °C, was found to be 48 ± 18 kJ molâ1 (N = 7) with a total range of 18-66 kJ molâ1.