EDTA acts as an inhibitor of:
Metalloprotease class distinguished by requirement zinc ion for catalytic mechanism and often calcium for structural integrity. Active site contains conserved motif HEXXH where histidines coordinate zinc plus third ligand histidine or glutamate forming tetrahedral geometry polarizing water molecule held nearby as hydroxide ion via general base glutamate abstracting proton making hydroxide nucleophile that attacks peptide carbonyl carbon forming tetrahedral transition state stabilized by zinc positive charge and nearby tyrosine oxyanion hole. Removal of zinc abolishes activity irreversibly. Eth
Ref: Lipscomb & Strater Chem Rev 1996 metalloprotease zinc HEXXH; Sigma EDTA chelation Zn Ca MMP inhibition detachment synergy.