rh-Polypeptide-31 is a single chain recombinant human peptide, produced by fermentation in E. coli. The starting gene is directly isolated from a human cell which codes for Insulin-Like Growth Factor 2 used as such or adapted to the production host. It contains a maximum of 180 amino acids which may contain disulfide bonds and/or glycosylation. The protein consists of the proper sequence of the 20 standard amino acids