Human MCP-1, generated by the proteolytic removal of the signal peptide and propeptide and has a calculated molecular mass of approximately 9 kDa. Recombinant MCP-1 is a disulfide-linked monomeric protein consisting of 77 amino acid residues and migrates as an approximately 9 kDa protein under non-reducing conditions and reducing conditions in SDS-PAGE. Optimized DNA sequence encoding human MCP-1 (CCL2) mature chain was expressed in E. coli.