Structure of the recombinant thrombopoietins

Left panel: rHuTPO (recombinant human thrombopoietin) (left) has a molecular structure identical to native thrombopoietin and is fully glycosylated. It consists of a carbohydrate-rich terminal domain (upper box) and an "erythropoietin-like" domain (lower box) which contains the receptor-binding region. Right panel: PEG-rHuMGDF (pegylated recombinant human megakaryocyte growth and development factor) consists of the "erythropoietin-like" domain only and is stabilized by the presence of a 20 kDa polyethylene glycol (PEG) moiety on the amino terminus.