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signal sequencea PEPTIDE of about 15 to 30 AMINO ACIDS at the N-terminus of certain newly synthesized PROTEINS. The peptide can mediate transport of such a protein across the ENDOPLASMIC RETICULUM or CELL MEMBRANE. It is afterwards cleaved from the protein. Leader peptides can be exploited in GENE CLONING in order to export foreign proteins to the exterior of HOST cells.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005