Small-molecule inhibitor: EDTA

Name

History: As a well known chelating agent, the ability of EDTA to inhibit metal-dependent enzymes has long been known.
Peptidases inhibited: Most metallopeptidases are inhibited, as are calcium-dependent cysteine peptidases including the calpains in family C2 and clostripain in family C11 (Mitchell & Harrington, 1970).
Mechanism: Inhibition of a metallopeptidase normally results from removal of the metal ion (commonly zinc). The metal ion may be very tightly bound to the enzyme, with a long half-time for dissociation, in which case inhibition by EDTA may be so slow as to be undetectable (Auld, 1995). If the metal-free apoenzyme is stable, it can be reactivated by micromolar concentrations of appropriate metal ions; higher concentrations may be inhibitory (Larsen & Auld, 1991).
DrugBank: DB00974

CID at PubChem: 6049
ChEBI: 42191
Structure
Chemical/biochemical name: 2-[2-[bis(carboxymethyl)amino]ethyl-(carboxymethyl)amino]acetic acid
Formula weight: 292

Inhibitor class: This compound is of the metal chelator class. Metal chelators contain anionic or neutral oxygen, nitrogen or sulfur atoms spatially arranged so as to give bi-, tri- or tetradentate ligation to a metal atom. Chelators can inhibit metalloenzymes either by removal of the metal from the enzyme or by binding to it to form a ternary complex (Auld, 1995).
Comment: 1,10-Phenanthroline (q.v.) is much more selective than EDTA for the chelation of zinc over calcium ions, and is therefore more appropriate as a diagnostic reagent for a metallopeptidase (Salvesen & Nagase, 2001).
Reviews: Auld (1988)