Table 3 Inhibition of intracellular proteasomal activities and cytotoxicity of PKS21221

From: Structure of human immunoproteasome with a reversible and noncompetitive inhibitor that selectively inhibits activated lymphocytes

IC50a (nM)

EC50a (nM)

Karpas β5i

Karpas β5(i+c)

HepG2 β5c

MM.1S

RPMI 8226

Karpas

HepG2

172 ± 33

118 ± 33

1833 ± 138

78 ± 30

66 ± 6

740 ± 145

2320 ± 630

  1. β5i activity was assayed with (Ac-ANW)2-R110
  2. β5(i+c) and β5c activity were assayed with suc-LLVY-luciferin
  3. β5(i+c) defines the total chymotryptic activity inside the Karpas cells
  4. aData are means ± SEM of three to four independent experiments
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