Isolation of Metarhizium anisopliae carboxypeptidase A with native disulfide bonds from the cytosol of Escherichia coli BL21(DE3)

► We describe the production of a fungal carboxypeptidase in the cytosol of Escherichia coli. ► The zymogen is kept soluble by fusing it to E. coli maltose-binding protein. ► Co-expression of DsbC in the cytosol promotes the formation of disulfide bonds. ► The zymogen is activated by digestion with thermolysin. ► Active carboxypeptidase is purified by affinity and conventional chromatography.