Table 1.
Binding parameters obtained for R- and S-propranolol on a VLDL column at various temperaturesa
| Enantiomer & binding model | Temperature (°C) | mL1 (mol) | Ka1 (M−1) | nKab (M−1) |
|---|---|---|---|---|
| R-Propranolol, Two interactions: saturable + non-saturable | 20 | 0.96 (± 0.47) × 10−8 | 9.2 (± 4.8) × 104 | 3.0 (± 0.3) × 106 |
| 27 | 1.3 (± 0.8) × 10−8 | 7.3 (± 4.3) × 104 | 2.9 (± 0.5) × 106 | |
| 37 | 1.3 (± 0.5) × 10−8 | 7.0 (± 2.3) × 104 | 1.2 (± 0.3) × 106 | |
| S-Propranolol, Two interactions: saturable + non-saturable | 20 | 1.6 (± 0.8) × 10−8 | 6.9 (± 3.4) × 104 | 2.5 (± 0.5) × 106 |
| 27 | 2.5 (± 0.9) × 10−8 | 4.6 (± 1.3) × 104 | 1.8 (± 0.4) × 106 | |
| 37 | 0.78 (± 0.16) × 10−8 | 9.6 (± 2.2) × 104 | 2.4 (± 0.6) × 106 |
The numbers in parentheses represent a range of ± 1 S.D. All of these results were measured in pH 7.4, 0.067 M potassium phosphate buffer.
The value for nKa for a non-saturable interaction was obtained by dividing the best-fit result for mLKa by the estimated moles of VLDL in the column. This latter value was obtained by using the protein content of the VLDL support, determined using an average molar mass for VLDL of 6.9 × 106 g/mol and a typical protein content for VLDL of 8% (w/w) [8,10,12-14].