Table III.
Kinetic Parameters of Streptavidin S52G mutant
| kon (M−1 sec−1) | koff (sec−1) | koff *(sec−1) | |
|---|---|---|---|
| wt streptavidin | |||
| Biotin | 6.8 × 107 ± 5.0 × 106 | ND | – |
| Biotin-4-fluorescein | 5.5 × 107 ± 1.0 × 106 | 3.3 × 10−5 ± 3 × 10−7 | – |
| S52G streptavidin | |||
| Biotin | 1.4 × 107 ± 1.0 × 106 | ND | ND |
| Biotin-4-fluorescein | 5.9 × 106 ± 1.0 × 105 | 2 × 10−4 ± 2 × 10−6 (20%) | 3 × 10−6 ± 5 × 10−8 (80%) |
koff corresponds to the values for the single exponential fit (wild type) or the first exponential of a double exponential fit (S52G mutant).
Koff* is the value for the second exponential of double exponential fit for S52G mutant. The amplitude in percentage of the first or second phase for the second exponential fit of S52G mutant is reported in parentheses.