Mature Myostatin is obtained by proteolytic processing of a biologically-inactive precursor protein, which contains an N-terminal propeptide of 243 amino acid residues. Myostatin Propeptide exhibits high binding affinity for myostatin and has been shown to be a potent inhibitor of Myostatin. Over-expression of myostatin propeptide in mice resulted in large increases (up to 200%) in skeletal muscle mass, similar to those observed in Myostatin knockout mice. Recombinant Human Myostatin Propeptide is a 27.8 kDa protein consisting of 244 amino acid residues.