Method for refining protein including self-cutting cassette and use thereof

The present invention relates to a self-cutting fusion protein including sequentially a target protein, a peptide consisting of an amino acid sequence of LPXTG, a sortase A cutting function domain, and a tag from the amino terminal; a coding nucleic acid thereof; an expression vector of the present invention including a nucleic acid; and a cell transformed by the expression vector of the present invention. The present invention also relates to a target protein refinement method including the steps of culturing, dissolving, and refining the transformed cell. The present invention relates to a self-cutting fusion protein including a self-cutting cassette which consists of a sortase A cutting function domain and a peptide consisting of an LPXTG amino acid sequence that is a recognition sequence thereof, and is very useful in that the steps of refining a target protein and eliminating the tag thereof can be accomplished by a single refinement step instead of separate steps. Particularly, the invention may be employed in various fields requiring a huge amount of a protein of a high purity in that a target protein existing in an amino terminal enhances the column union ability and the self-cutting ability of a fusion protein, a target protein rid of the tag is obtained with a high purity, a cutting-buffer makes the steps of refining and eliminating the tag be accomplished through a single step, significantly reducing the time and efforts needed for refining, and the accomplishment through a single step reduces the loss of the protein yield. Particularly, the invention is useful for manufacturing a therapeutic antibody-drug complex.