Table 1

Photoaffinity labeling of 26S proteasome with NAB-ADM

The purified 26S proteasome (570 μg/ml) was incubated with 10 μm NAB-ADM at 4°C for 3 h. After incubation, unbound NAB-ADM was removed by gel chromatography and UV irradiated (312 nm) at 4°C for 5 min. Suc-LLVY-MCA-hydrolyzing activity and content of the photocovalent adduct were measured as described in the text. Control protease activity was measured in the absence of NAB-ADM.
Photoaffinity labelingProtease activity (control %)NAB-ADM
μmnmol/mg protein
97.710.0 (added)17.5 (added)