Figure 1.
(A) Chemical structures of peptide-based competitive inhibitors bortezomib and MG132, and (B) non-competitive proteasome, small molecule inhibitor, TCH-013. (C) TCH-013 inhibits the CT-L and Casp-L activity of the human proteasome. Fluorogenic substrates Suc-LLVY-AMC, Z-ARR-AMC and Z-LLE-AMC were used to measure CT-L, T-L and Casp-L activities of purified human 20S proteasome particles as described in material and methods. The maximum increase in fluorescence per minute was used to calculate specific activities of each sample. (D) Fluorogenic substrates Suc-LLVY-AMC. Z-ARR-AMC and Z-LLE-AMC were used to measure CT-L, T-L and Casp-L activities of fully assembled proteasomes extracted from RPMI-8226 human multiple myeloma cells with ATP/DTT buffer as described in materials and methods. The maximum increase in fluorescence per minute was used to calculate specific activities of each sample.