COMPREHENSIVE BUFFER SYSTEM FOR RENATURING HUMAN PROINSULIN OR PROINSULIN DERIVATIVES

摘要

The invention relates to an improved processing and purification method for the production of proinsulin or derivatives thereof starting from the solubilisation of inclusion bodies isolated from a prokaryotic expression system, such as E. coli, whereby all processing (i.e. refolding, precipitation, concentration) and purification steps are carried out in the same aqueous buffer system comprising an organic amphoteric substance containing at least two functional groups, which contain at least an amino and a carboxylic acid group, and which is characterized by a difference in the pKa values of its at least one amino group and at least one carboxylic acid group of at least 7. Furthermore, the organic amphoteric substance is an efficient scavenger of cyanate, thereby preventing irreversible carbamylation of primary amines present in proinsulin or the derivates thereof, which has been observed in the presence of high concentrations of urea. Thus, the disadvantage associated with this widespread chaotropic auxiliary is obliterated, allowing the utilization of efficient and uncomplicated chromatography techniques for purification steps subsequent to solubilisation and refolding. The use of an efficient buffer substance in all processing steps from inclusion body solubilisation up to the re-folded, concentrated and purified precursor of insulin or a derivate thereof, which at the same time acts as an agent preventing protein modification by carbamylation, thereby abolishing the need to add an additional compound with scavenging activity, leads to significant advantages regarding the efficiency and efficacy of the procedure compared to previously employed production methods.