TABLE 3.
ATPase activity parameters and extent of autophosphorylation for DnaK and DnaK derivatives
| DnaK | ATPase activitya
|
Extent of autophosphorylationb | ||
|---|---|---|---|---|
| Vmax (pmol of ATP/μg of DnaK/min) | kcat (min−1) | Km (nM) | ||
| Wild type | 2.29 | 0.158 | 27.5 | 1.00 |
| T199S | 1.73 | 0.120 | 36.5 | 0.129 |
| T199A | 0.0696 | 0.00481 | 19.1 | 0 |
| K70A | 0.0808 | 0.00558 | 41.8 | 0 |
a
The Vmax, Kcat, and Km values were derived from the y intercept and slope of the Eadie-Hofstee plots (Fig. 1).
b
The extent of autophosphorylation was determined as described in Materials and Methods. The extent of autophosphorylation of wild-type DnaK was set as 1.00.