To Reset the structure at any time

The structure of Dihydrolipoyl Transacetylase has one binding site for lipoic acidand one site for CoA. These sits are where the action of the enzyme takes place. The enzyme need the other subunits to function since the lipoamide cofactor of E2 reacts with the product (hydroxyethyl-TPP) from E1, and (in its modified form, dihydrolipoamide, formed by the third step) interacts with E3. It is for this reason that the interaction rate is increased by proximity of all three enzymes, and in fact the lipoamide group is a long flexible arm about 14Å long. It is covalently bonded to a specific lysine residue of the enzyme. The movement of the arm may be driven by a change in the net charge of the lipoyl group, depending on the ionization of the sulphydryl groups.

The key control for this enzyme is competitve binding of the reduced and unreduced forms of the substrate and the regeneration of the substrates by the other pieces of this multienzyme complex(Fig. 1).