Jintropin is a recombinant human growth hormone (rhGH) produced by gene recombination E. Coli secretion expression technology. Its precursor synthesized in E. Coli including gene of human growth hormone(hGH) was secreted to periplasmic space of the cell guided under signal peptide. The signal peptide was removed and polypeptide molecule is folded exactly to growth hormone (GH) molecule. Jintropin has 191 amino acid residues and a molecular weight of 22125 daltons. It’s amino acid content, structure and sequence are identical to those of HGH.