Structural basis for the potent calpain inhibitory activity of peptidyl alpha-ketoacids.

A series of peptidyl alpha-ketoacids and alpha-ketoesters was synthesized and studied as mu-calpain inhibitors. Docking studies revealed that the mu-calpain inhibitory activity of the compounds is influenced by hydrogen bonding interactions and the potential for ionic interaction with active site residues as well as placement of a planar N-terminal capping group into the S 3 pocket of the enzyme.