sr-Cow Polypeptide-5 is a single chain recombinant protein produced by fermentation in E. coli. The starting gene is synthetically produced to be identical to a portion of the gene which codes for Insulin-Like Growth Factor 1, which is found in the cow, Bos taurus. The protein contains a maximum of 154 amino acids which may contain disulfide bonds and/or glycosylation, and consists of the proper sequence of the 20 standard amino acids.