Table 2. Relative inhibitory effects of 22 and cCNGRC (26) against porcine Aminopeptidase N (APN) ^a .

Entry	Compound	IC50 (μM)
1	22	175
2	cCNGRC (26)	212 b
3	bestatin c	4.1 b

^aAPN and the substrate l-leucine-p-nitroanilide were incubated for 1 h in the presence of gradient concentrations of inhibitors and formation of the product p-nitroaniline measured reading absorbance at 405 nm. IC₅₀ values were calculated from concentration–response curves (see ESI).

^bValues slightly lower than those reported in ref. 19.

^cPositive control.