However, when the recombinant proFgCatB3 with the c-myc epitope and hexahistidine tag at the C-terminus was expressed in the yeast Pichia pastoris GS115, using the pPICZaA vector designed to secrete recombinant proteins into the extracellular culture media, SDS–PAGE analysis of the recombinant protein eluted from the Ni2+-NTA column revealed a minor band at about 38–39 kDa, while the bulk of the protein migrated as a smear ranging from 55–75 kDa.