Novel synthetic peptide and use thereof

Provided are a synthetic peptide for inducing the reprogramming of differentiated cells, a pharmacological composition for inducing reprogramming including this synthetic peptide, and a method for producing undifferentiated cells from differentiated cells using this synthetic peptide. The peptide provided by the present invention is a synthetic peptide having a reprogramming-inducing peptide sequence comprising an amino acid sequence shown by SEQ ID NO: 1 or a modified amino acid sequence thereof. The method for producing undifferentiated cells also provided by the present invention includes culturing a cell culture that includes target cells that have supplied this synthetic peptide and inducing reprogramming of the target cells.