The present invention discloses novel macromolecule transduction domain (MTD) peptides which facilitate the traverse of a biologically active molecule across the cell membrane. Also disclosed are polynucleotides encoding the MTD peptides, methods of identifying the MTD peptides; methods of genetically engineering a biologically active molecule to have cell permeability by using the MTD peptides, methods of importing a biologically active molecule into a cell by using the MTD peptides, and uses thereof.