GDNF is a disulfide-linked, homodimeric neurotrophic factor structurally related to Artemin, Neurturin and Persephin.? These proteins belong to the cysteine-knot superfamily of growth factors that assume stable dimeric protein structures.? GDNF signals through a multicomponent receptor system, composed of a RET and one of the four GFRα (α1-α4) receptors.? GDNF specifically promotes dopamine uptake and survival, and morphological differentiation of midbrain neurons.? Using a Parkinson’s disease mouse model, GDNF has been shown to improve conditions such as bradykinesia, rigidity, and postural instability.? The functional rat GDNF ligand is a disulfide-linked homodimer consisting of two 15 kDa polypeptide chains called monomers.? Each monomer contains seven conserved cysteine residues, including Cys-101, which is used for inter-chain disulfide bridging, and others that are involved in the intramolecular ring formation known as the cysteine knot configuration. The calculated molecular weight of Recombinant Rat GDNF is 30.0 kDa.