Table 3.

Inhibition of the chymotryptic-like activity of purified human 20S proteasome by compounds 11–33. Data are averages of a minimum of two independent experiments, each as a technical triplicate. Individual values and standard error of the means are listed in supplemental Table S1

	R1	R2	R3	IC50(μM)
11	H	Phenyl	Phenyl	>10
12	Acetyl	Phenyl	Phenyl	>10
13	Benzoyl	Phenyl	Phenyl	>10
14	Tosyl	Phenyl	Phenyl	>10
15	CH2-2-furan	Phenyl	Phenyl	7.04a
1	Benzyl	Phenyl	Phenyl	2.58
16	4-CH3O-benzyl	Phenyl	Phenyl	2.73
17	4-F-benzyl	Phenyl	Phenyl	3.71
18	4-Cl-benzyl	Phenyl	Phenyl	2.02
19	4-Br-benzyl	Phenyl	Phenyl	1.90
20	Benzyl	4-pyridine	Phenyl	>10
21	Benzyl	2-furan	Phenyl	6.13
22	Benzyl	4-NO2-phenyl	Phenyl	6.71
23	Benzyl	4-NH2-phenyl	Phenyl	3.52
24	Benzyl	4-CF3-phenyl	Phenyl	4.81
25	Benzyl	4-Cl-phenyl	Phenyl	2.23
26	Benzyl	4-NH(SO2Ph)-phenyl	Phenyl	1.08
27	Benzyl	4-SCH3-phenyl	Phenyl	2.77
28	Benzyl	4-SO2CH3 – phenyl	Phenyl	>10
29	Benzyl	4-NHBenzyl-phenyl	Phenyl	0.47
30	Benzyl	Phenyl	4-Br-phenyl	3.19
31	Benzyl	Phenyl	4-CH3O-phenyl	1.27
32	Benzyl	4-CN-phenyl	4-CH3O-phenyl	>10
33	Benzyl	4-CONH2-phenyl	4-CH3O-phenyl	>10

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