Monitoring proteolysis of recombinant human interferon-γ during batch culture of Chinese hamster ovary cells

摘要: Proteolytic cleavage of recombinant human interferon-γ (IFN-γ) expressed in Chinese hamster ovary (CHO) cells during batch fermentation has been monitored by mass spectrometric peptide mapping. IFN-γ was purified from cell-free culture supernatant immunoaffinity chromatography and cleaved endoprotease Asp-N. Peptide fragments were resolved reverse-phase HPLC identified a combination matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) spectrometry (MS) automated N-terminal sequencing. Using this approach, as the C-terminal fragment polypeptide. Analysis MS indicated that polypeptide secreted CHO truncated at least ten amino acids, initially Gln133-Met134. No full length (143 acids) molecules observed any stages fermentation. Additional proteolytic cleavages basic acids Gln133 occurred later resulting heterogeneous population with 'ragged' C-termini.