Snapshots of the reaction mechanism of matrix metalloproteinases

The series of events that occur in the catalytic cycle of matrix metalloproteinases were modeled on the basis of X-ray crystal structures of the active, uninhibited enzymes and of the same enzymes followingthe hydrolysis of a peptide substrate. After the peptide bond has been broken, both peptide fragments remain bound to the protein initially (see structure of the active-site cavity of the enzyme MMP-12 immediately after substrate hydrolysis).