Substrate entasis and electronic coupling elements in electron transfer from FeII in a multicopper ferroxidase

Entasis in architecture renders a form to appear other than it physically is; entasis in enzymology is an enzyme active site that renders the substrate more reactive than it chemically is. Multicopper oxidases that exhibit specificity for ferrous iron do so by providing a substrate binding site more favorable to FeIII and by stabilizing the product state catalyze electron transfer from FeII specifically.