the mechanism of inhibition of VW, IW and IPP for the individual ACE domains was determined using the substrates Abz- SDK(Dnp)P-OH for the N-domain activity and Abz-LFK(Dnp)-OH for the C-domain activity. To identify the type of inhibition, the direct fit to the Michaelis–Menten equation (for substrates Abz- SDK(Dnp)P-OH) and to the Hill equation