Efficient production of recombinant cystatin C using a peptide-tag, 4AaCter, that facilitates formation of insoluble protein inclusion bodies in Escherichia coli

► Recombinant cystatin C was produced using a 4AaCter peptide-tag system. ► Recombinant cystatin C fused with 4AaCter formed protein inclusion bodies in E. coli. ► Highly purified cystatin C was obtained without complicated purification steps. ► Highly immunoreactive recombinant cystatin C was produced using this system.