Figure 1.

Small molecule inhibitors inhibit chymotrypsin‐like activity of human immunoproteasome. A, Chemical structures of Bortezomib and ONX 0914. B, Human constitutive proteasome or immunoproteasome preparations were incubated with fluorogenic substrate Suc‐LLVY‐AMC in the presence of various Bortezomib or ONX 0914 inhibitor concentrations as indicated. Data show percentage inhibition calculated as described in material and methods as mean ± SEM of one representative experiment (each concentration in duplicate). C, Table showing inhibitory potencies summarized from 12 (Bortezomib) and 33 (ONX 0914) number of tested (fitted) concentration response curves performed in duplicates for the human constitutive proteasomes and 23 (Bortezomib) and 111 (ONX 0914) number of tested (fitted) concentration response curves performed in duplicates for the human immunoproteasomes