sr-Cat Polypeptide-3 is a single chain recombinant protein produced by fermentation in E. coli. The starting gene is synthesized to be identical to the gene which codes for Fibroblast Growth Factor 2 derived from cat. The parent protein contains a maximum of 155 amino acids which may contain disulfide bonds and/or glycosylation, and consists of the proper sequence of the 20 standard amino acids.