Recombinant human GGF2 (Glial growth factor) is a disulfide-linked monomeric protein consisting of 315 amino acid residues, and migrates as an approximately 34 kDa protein under non-reducing and reducing conditions in SDS-PAGE. Optimized DNA sequence encoding Human Neuregulin-1 isoform 9 (GGF2) was expressed in E. coli.