HBEGF is growth factor that mediates its effects via EGFR, ERBB2 and ERBB4. It is required for normal cardiac valve formation and normal heart function. This protein promotes smooth muscle cell proliferation. It may be involved in macrophage-mediated cellular proliferation. It is mitogenic for fibroblasts, but not endothelial cells. It is able to bind EGF receptor/EGFR with higher affinity than EGF itself and is a far more potent mitogen for smooth muscle cells than EGF. Recombinant human HBEGF protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.