Aminoketone 1, a Psi[CO-CK] dipeptide mimic of glycylproline, is a pot
ent, competitive inhibitor (K-i = 270 +/- 24 nM) of porcine kidney pro
lidase, a Mn(II)-dependent dipeptidase, whereas the homologous aminoke
tone 2 and its non-cyclic analogue delta-amino-levulinic acid, 3, are
significantly less inhibitory (K-i approximate to 1 mM).