Fig. 1.

AsnEDAs noncompetitively inhibit β5i and β5c. a Dipeptide DPLG3 and AsnEDA PKS21004 and PKS21003. b PKS21004 potently and dose-dependently inhibits β5i and β5c, whilst PKS21003 is inactive. c PKS21004 reversibly inhibits β5c. d–g kinetics studies of modality of inhibition for PKS21004 against β5i (d, e) and β5c (f, g). d Steady state velocities in the presence of PKS21004 at the concentrations indicated next to each curve. Data as in d are shown in double reciprocal plots in e, and data from f in g. Values of Ki and α for PKS21004 were determined to be 0.077 µM and 0.28 µM for β5i, and 0.55 µM and 0.65 for β5c, respectively, by fitting the data to an equation for noncompetitive inhibitors. Data are means ± SEM of three independent experiments