ChEBI: L-685,458 is a peptide and carboxamide that is L-leucyl-L-phenylalaninamide, L-Leu-L-Phe-NH2, which has been acylated on the N-terminus by a Phe-Phe hydroxyethylene dipeptide isotere, 2R-benzyl-5S-tert-butoxycarbonylamino-4R-hydroxy-6-phenylhexanoic acid. Compounds based on the structure of L-685,458 are potent inhibitors of gamma-secretase, which mediates the final catalytic step that generates the amyloid beta-peptide (Abeta), which assembles into the neurotoxic aggregates in the brains of sufferers of Alzheimer's disease. It has a role as a peptidomimetic and an EC 3.4.23.46 (memapsin 2) inhibitor. It is a secondary alcohol, a peptide, a carbamate ester and a monocarboxylic acid amide. It contains a tert-butoxycarbonyl group.