I’m looking for advice regarding inhibition of kinases with specific chemical inhibitors.
For instance, cdk1/cyclin B with the inhibitor RO-3306. In Vassilev et al, PNAS, 2006, it’s indicated that the Ki for cdk1/cyclin B is 35 nM and it's 110 nM for cdk-1/cyclin A.
For my experiment, I would like to inhibit only cdk1/cyclinB in a cell extract (not within cells in culture). What concentration would you suggest to use? 35 nM (exactly corresponding to the Ki) or a little bit more such as 40 or 50 nM to be sure of reaching a total inhibition?