sh-Polypeptide-45 is a single chain recombinant human peptide, produced by fermentation in E. coli. The starting gene is synthesized to be identical to the human gene which codes for Granulocyte Macrophage Colony Stimulating Factor. It contains a maximum of 144 amino acids which may contain disulfide bonds and/or glycosylation. The protein consists of the proper sequence of the 20 standard amino acids