LDN 57444 is an inhibitor of ubiquitin C-terminal hydrolase-L1 (UCH-L1) activity with a Ki of 0.4 µM. UCH-L1 is a deubiquitinating enzyme that is abundantly expressed in the brain, and its activity is required for normal synaptic function. Inhibition by LDN 57444 causes cell death through the apoptosis pathway, increases levels of highly ubiquitinated proteins and decreases ubiquitin proteasome activity.
