Method for producing a natriuretic peptide with a pI above 8 or below 5

摘要

A method is described for producing a peptide having a pI above 8 or below 5 wherein the peptide is expressed as a fusion protein in which it is linked to a fusion partner through an acid cleavage site. The peptide is released from the fusion partner by acid cleavage in the absence of chaotrope. The fusion partner and its acid cleavage products, if any, have a net charge sufficiently different from that of the desired peptide to allow isolation of the peptide by ion-exchange chromatography.