sh-Polypeptide-57 is a single chain synthetic human peptide, produced by fermentation in E. coli. The starting gene is synthesized to be identical to the human gene which codes for Protein Disulfide Isomerase used as such or adapted to the production host. It contains a maximum of 508 amino acids which may contain disulfide bonds and/or glycosylation. The protein consists of the proper sequence of the 20 standard amino acids.