The chemistry and biochemistry of hemec: functional bases for covalent attachment

Abstract

Covering: up to July 2008

A discussion of the literature concerning the synthesis, function, and activity of hemec-containing proteins is presented. Comparison of the properties of hemec, which is covalently bound to protein, is made to heme b, which is bound noncovalently. A question of interest is why nature uses biochemically expensive hemec in many proteins when its properties are expected to be similar to heme b. Considering the effects of covalent heme attachment on heme conformation and on the proximal histidine interaction with iron, it is proposed that heme attachment influences both heme reduction potential and ligand–iron interactions.