Structural stability and heme binding potential of the truncated human dual oxidase 2 (DUOX2) peroxidase domain

► Human DUOX1 cannot substitute for DUOX2 in thyroid hormone synthesis. ► DUOX2 like DUOX1, yields a protein that does not co-purify with heme. ► DUOX2 peroxidase-like domain is more structurally stable than that of DUOX1. ► Heme titrations show both DUOX peroxidase-like domains bind heme weakly. ► Tighter heme binding may require interaction with a protein partner such as DUOXA2.