Table 1. Inhibitory Activity of N-Benzoyl-Capped Tripeptides with Various C-Terminal Amino Acids, Possessing the General Structure (Bz-Arg-Lys-X-NH₂) against DENV and WNV Proteases and Thrombin^a.

		DENV		WNV	THR
	X	%b	IC50 (μM)c	%d	%e
1	Nle	68.122	13.3(23)	7.722	5.522
2	Ser	57.9	30.1	21.9	6.2
3	Phe	80.7	11.9	18.2	7.2
4	Ala	46.6	35.6	26.0	7.2
5	Gly	70.4	21.0	44.6	3.5
6	Met	45.0	47.5	11.8	6.2
7	Nrv	62.0	25.2	8.5	n.i.
8	Tle	18.8	137.2	11.7	n.i.
9	Phg	95.0	3.3	39.3	n.i.
10	Tic	41.6	65.8	17.8	n.i.
11	d-Nle	72.7	14.1	16.1	4.9
12	2-Abz	62.0	15.8	8.7	6.4
13	Trp	74.1	17.6	32.8	n.i.
14	Tyr	82.3	7.4	12.9	7.9
15	β-Ala	32.9	109.3	19.8	n.i.
16	Aib	55.0	46.7	13.7	n.i.
17	Pro	20.0	191.9	3.6	n.i.
18	3-Abz	27.0	96.6	23.0	5.6
19	4-Abz	27.5	92.2	17.9	9.2
20	Pra	72.5	17.5	14.3	5.2
21	Pip	13.7	159.2	12.1	n.i.
22	3-Pal	61.3	30.1	12.5	n.i.
23	2-Pal	53.0	44.3	9.8	n.i.
24	(4-NO2)Phe	66.6	17.5	21.3	n.i.
25	(4-CN)Phe	71.7	14.4	15.9	n.i.
26	Cha	80.0	8.2	19.1	n.i.
27	Chg	71.7	17.4	12.1	n.i.
28	Leu	63.2	22.7	18.4	5.9
29	Ile	56.6	28.2	14.9	4.6
30	Thr	32.1	98.6	16.5	n.i.
31	Val	60.0	28.8	18.3	4.9

^an.i. = no inhibition. All measurements were carried out in triplicate. Standard deviations were below 10%.

^bPercent inhibition of DENV NS2B-NS3 protease serotype 2 (enzyme 100 nM, inhibitor 50 μM, substrate 50 μM, K_m = 105 μM).

^cIC₅₀ values against DENV NS2B-NS3 protease serotype 2 were determined for a substrate concentration of 50 μM.

^dPercent inhibition of WNV NS2B-NS3 protease (enzyme 150 nM, inhibitor 50 μM, substrate 50 μM, K_m = 212 μM).

^ePercent inhibition of thrombin (enzyme 10 nM, inhibitor 25 μM, substrate 50 μM, K_m = 16 μM).