8RK64 is a covalent inhibitor of ubiquitin C-terminal hydrolase L1 (UCH-L1; IC50 = 0.32 µM) and a click chemistry reagent.[1] It is selective for UCH-L1 over UCH-L3 and UCH-L5 (IC50s = 216 and >1,000 µM, respectively). 8RK64 has been linked to fluorophores containing alkyne groups via copper(I)-catalyzed azide/alkyne cycloaddition (CuAAC) and used to visualize UCH-L1 activity in cells.
References:
[1].Kooij, R., Liu, S., Sapmaz, A., et al.Small-molecule activity-based probe for monitoring ubiquitin C-terminal hydrolase L1 (UCHL1) activity in live cells and zebrafish embryosJ. Am. Chem. Soc.142(39)16825-16841(2020).