KLF4 is a member of the Kruppel-like factor (KLF) family of zinc finger transcription factors. Members of this family share 3 contiguous C2H2-type zinc fingers at the carboxyl terminus that comprise the DNA-binding domain. KLF4 is highly expressed in skin and gut epithelial tissues, but is also found in various other cells and tissues, including vascular endothelial cells, lymphocytes, lung, and testis. It is an important regulator of the cell cycle, transcription, and cell differentiation. Together with Sox2, Oct4, and cMyc, KLF4 can induce the reprogramming of primary human fibroblasts to a pluripotent state. KLF4 and other transcription factors can be introduced into cells by DNA transfection, viral infection, or microinjection. Protein transduction using TAT fusion proteins represents an alternative methodology for introducing transcription factors into primary, as well as transformed, cells. Recombinant Human KLF4-TAT is a 483 amino acid protein, including a 13-residue C-terminal TAT peptide, with a calculated molecular weight of 51.7 kDa. PeproTech’s Recombinant Human KLF4-TAT is a mixture of the expected sequence beginning at Met1 and a truncated isoform beginning at Tyr54. Due to post-translational modifications, SDS-PAGE gel shows bands at approximately 72 and 66kDa, under reduced conditions.