Fig 4. Effect of different inhibitors on the enzymatic activity of YkfC_Ctr.

TLC analysis of the inhibiting effect of chloroacetone, iodoacetamide, and E-64 on YkfC_Ctr activity. (a) The alkylating chemical chloroacetone proved to be the most potent inhibitor as shown by the absence of the reaction product mDAP at a molar inhibitor:protein ratio of 8:1. YkfC_Ctr retained activity at lower molar ratios (F Fig in S1 Text). (b) The second alkylating compound iodoacetamide did not show a significant inhibitory effect on YkfC_Ctr activity. (c) The cysteine protease inhibitor E-64 carrying a trans-epoxysuccinic acid group coupled to a dipeptide was able to inhibit YkfC_Ctr at a molar ratio of 10:1.