QUANTIFYING BIOSYNTHETIC HUMAN GROWTH-HORMONE IN ESCHERICHIA-COLI WITH CAPILLARY-ELECTROPHORESIS UNDER HYDROPHOBIC CONDITIONS

A method has been developed which is able to quantitate the content of precursor biosynthetic human growth hormone (Pre-bhGH) in the cytosol of E. coli cells containing the gene for human growth hormone (hGH). The method uses hydrophobic C-18 coated capillaries with native biosyn thetic human growth hormone (bhGH) as an internal standard. This allow s for highly robust and precise determinations as well as the evaluati on of the presence of deamidated forms in the cytosol samples. Further more, by modifying the running buffer with zwitterionic surfactants an d an organic modifier, it is possible to detect a related form with a three sulfur atom Cys-Cys bridge (trisulfide Pre-bhGH). Thus, a strong tool for monitoring the effect of fermentation conditions on the bios ynthesis of bhGH is obtained. (C) 1998 Elsevier Science B.V. All right s reserved.