Selective and reversible thiol-pegylation, an effective approach for purification and characterization of five fully active ficin (iso)forms from Ficus carica latex

► We purified near to homogeneity five ficin (iso)forms from Ficus carica latex. ► CD data showed similar secondary and tertiary structures to papain family enzymes. ► Mass spectrometry analyses clearly identified at least four different forms. ► Enzymatic activity measurements suggested different substrate specificities. ► Inhibitory activity confirmed the cysteine proteases nature of all ficin forms.