Modified and stabilized propeptides of Growth Differentiation Factor proteins, such as GDF-8 and Bone Morphogenetic Protein-11, are disclosed. The system also includes an alignment system having an electronic controller, input and output adaptors configured to rotate with the drive shaft, one or more adjustment discs, and an adjustment mechanism. The high density portion is positioned between the low density portions. This groove limits the migration of hydrogen ions to adjacent unit cells to prevent reduction in voltage.