ransdermal Peptide is a 11-amino acid peptide, binds to Na+/K+-ATPase beta-subunit (ATP1B1), and enhances the transdermal delivery of many macromolecules. Transdermal Peptide (TD1) binds to ATP1B1, and mainly interacts with the C-terminus of ATP1B1 in yeast and mammalian cells. The interaction affects the expression and localization of ATP1B1 and epidermal structure, but can be antagonized by the exogenous competitor ATP1B1 or be inhibited by ouabain. Inhibition of Transdermal Peptide binding to ATP1B1 causes decreased delivery of macromolecular drugs across the skin.