ChEBI: N-benzyloxycarbonyl-L-leucyl-L-leucyl-L-leucinal is a tripeptide that is L-leucyl-L-leucyl-L-leucine in which the C-terminal carboxy group has been reduced to the corresponding aldehyde and the N-terminal amino group is protected as its benzyloxycarbonyl derivative. It has a role as a proteasome inhibitor. It is a tripeptide, an amino aldehyde and a carbamate ester.