Growth/Differentiation Factor 5 (GDF-5) is a growth factor that regulates cell prolife ion and differentiation in embryonic and adult tissues. GDF-5 is part of the TGF family of Proteins and is closely related to the BMP family of Proteins. Recombinant GDF-5 is a non-glycosylated homodimer, containing two 117 amino acids chains, with a total molecular weight of 26.8 kDa. To enable bacterial expression the N-terminal sequence of Ala-Pro-Leu-Thr was replaced with a Lys.