Optimized refolding and characterization of S-peroxidase (CWPO_C of Populus alba) expressed in E. coli

► Cationic cell wall peroxidase from poplar tree was expressed in Escherichia coli as an inclusion body. ► The optimal conditions for refolding CWPO_C were 100 mM Tris-HCl at pH 8.5, 0.6 mM GSSG, 5 μM hemin, 0.6 M GmdCl and 5 mM CaCl2. ► kcat/Km for sinapyl alcohol of CWPO_C was over 170 times higher than that of HRP_C. ► Refolded CWPO_C possesses a very unique property of S-peroxidase.