Figure 9.

Selectivity profile of stereochemically pure alkyne-based inhibitors 2a, 2b, and 28 (bottom) and corresponding nitriles (top). Shown are the negative decadic logarithms of the K_i values and the decadic logarithm of the inactivation constants k_inact/K_I. Thus, larger values are equivalent to higher inhibition potentials of the compounds. The measurement was performed in three independent experiments (each as a duplicate determination) in assay buffer (pH 6.0) with 1.5% DMSO. n.i. = no inhibition; i.e., no evidence of irreversible inhibition was discernible within the considered time and concentration ranges.