Table 2.
Association equilibrium constants (KaI) measured at Sudlow sites I and II for various sulfonylurea drug with normal HSA and in vivo glycated HSA.
| Binding site and column | KaI (× 104 M−1)a | ||
|---|---|---|---|
| Tolbutamide | Gliclazide | Acetohexamide | |
| Sudlow site I | |||
| Normal HSAb | 5.5 (± 0.2) | 1.9 (± 0.04) | 4.2 (± 0.4) |
| Glycated HSA-CS1 | 6.8 (± 0.5) | 2.3 (± 0.2) | 4.7 (± 0.3) |
| Glycated HSA-CS2 | 7.9 (± 0.4) | 1.4 (± 0.1) | 4.0 (± 0.4) |
| Sudlow site II | |||
| Normal HSAb | 5.3 (± 0.2) | 6.0 (± 0.5) | 13 (± 1.0) |
| Glycated HSA-CS1 | 7.3 (± 0.5) | 11 (± 1.0) | 13 (± 0.2) |
| Glycated HSA-CS2 | 7.9 (± 0.3) | 9.2 (± 0.7) | 17 (± 0.4) |
a
These binding parameters were calculated from data obtained at pH 7.4 and 37°C using the best-fit lines generated according eq (3). The values in parentheses represent a range of ± 1 S.D. for the population of results (n = 6–7, each measured in triplicate) and were determined by using error propagation with the standard deviations of the slopes and intercepts of the best-fit lines that were obtained when using eq (2).