Increased disulphide dimer formation of latent associated peptide fusions of TGF-β by addition of l-cystine

► Chinese Hamster Ovary (CHO) cells adapted for growth in suspension are a valuable tool for the medium scale production of recombinant protein. ► Addition of l-cystine to the culture medium of CHO-S cells increases the formation of disulphide bonds in LAP-fusion proteins. ► Use of the SV40 large T antigen to increase plasmid copy number increases the production of recombinant protein in CHO cells.