Recombinant Streptomyces Avidinii Streptavidin produced in E.Coli is a single, non-glycosylated polypeptide chain (25-183) containing a total of 167 amino acids and having a molecular mass of 17kDa. The Streptavidin protein is fused to an 8 aa N-terminal His-Tag and purified by proprietary chromatographic techniques.