Table 3.

Structure and inhibition data of S10 and C13 analogues.

Compound	Structure	% Inhibition with 100 µM compound	IC50 (µM)*
S10G		98.6 ± 2.4a 99.1 ± 1.5c	4.2 ± 0.3
S10L		89.0 ± 3.0a 90.5 ± 5.2c	4.4 ± 0.4
S10K		81.7 ± 2.0a 81.7 ± 3.4c	7.6 ± 0.8
S10D		96.3 ± 1.6a 53.3 ± 7.8b	9.8 ± 1.7
S10B		92.0 ± 6.7a 64.4 ± 14.7b	10.5 ± 2.4
S10C		96.8 ± 0.7a 62.9 ± 6.8b	11.0 ± 1.3
S10E		94.6 ± 1.1a 46.8 ± 7.4b	12.8 ± 1.8
S10F		93.7 ± 0.8a 52.5 ± 6.5b	12.9 ± 1.3
S10M		81.3 ± 3.3a 43.7 ± 3.1b	16.4 ± 3.1
S10H		92.3 ± 2.7a 53.4 ± 10.4b	16.5 ± 2.3
S10I		74.3 ± 5.8a 81.8 ± 4.6c	16.8 ± 2.2
S10P		59.3 ± 2.5a 44.7 ± 4.7b	79.9 ± 9.9
C13G		55.5 ± 8.8a	21.5 ± 2.0
C13F		43.2 ± 10.9a	27.0 ± 1.6
C13C		24.7 ± 1.7a	719 ± 76**
C13A		21.8 ± 2.5a	1545 ± 261**
C13B		2.3 ± 3.1a	1922 ± 300**
C13D		5.5 ± 4.1a	2047 ± 57**
C13E		−8.3 ± 1.7a	3370 ± 678**

^aFluorescence assay, ^bcolorimetric assay, ^cCasp6-C163A cleavage assay, ^*IC₅₀ values were determined using fluorescence assay, ^**approximate IC₅₀ values calculated from not-perfectly fitted dose-response curves due to limited compound solubility (C13A, C13C) or very low compound potency at the highest concentration tested (C13B, C13D, C13E).