Table 2.

Concentrations required for inhibition of catalytic activities of the proteasome by synthetic inhibitors.^[a]

	Kiapp = [I]/((vo/vs) – 1)[b]
	Chymotrypsin-like activity	PGPH activity	Trypsin-like activity
TMC-95A	1.1 ± 0.1 nm	29 ± 4 nm	0.81 ± 0.12 µm
TMC-95B	1.7 ± 0.1 nm	23 ± 3 nm	1.1 ± 0.1 µm
12	5.7 ± 0.8 nm	150 ± 20 nm	9.7 ± 3.5 µm
13	6.2 ± 0.4 nm	130 ± 20 nm	9.7 ± 2.4 µm
14	4.9 ± 0.4 nm	63 ± 2 nm	2.6 ± 0.2 µm
15	5.3 ± 0.5 nm	87 ± 12 nm	5.1 ± 0.5 µm
16	1.4 ± 0.1 nm	11 ± 1 nm	0.93 ± 0.11 µm
17	1.9 ± 0.2 nm	23 ± 6 nm	1.2 ± 0.3 µm
18	24 ± 2 nm	110 ± 20 nm	13 ± 2 µm
19	7.0 ± 5.0 µm	5.3 ± 0.6 µm	49 ± 34 µm
20	>100 µm	>100 µm	>100 µm
21	22 ± 10 µm	65 ± 25 µm	>100 µm
Epoxomicin aldehyde	7.0 ± 0.6 nm	2.6 ± 0.1 µm	0.35 ± 0.06 µm

^[a]The concentrations required for inhibition of the three major proteasome catalytic activities were determined for TMC-95A and B, their synthetic analogues, and for epoxomicin aldehyde for comparison.

^[b]The value v_o is the rate of enzyme activity in the absence of inhibitor, and v_s is the steady rate of inhibited enzyme activity.