Rodrigues, Margaridade la Torre, Beatriz G.Rádis-Baptista, GandhiSantos, Nuno C.Andreu, David2012-07-232012-07-232011Bioconjugate Chem. 2011, 22, 2339−23441043-1802http://dx.doi.org/10.1021/bc200421zhttp://hdl.handle.net/10451/6747© 2011 American Chemical SocietyNucleolar targeting peptides (NrTPs), a recently developed family of cell-penetrating peptides, have been shown to be very efficient in entering cells and accumulating in their nucleoli. In this work, we have used conjugates of NrTP6 (YKQSHKKGGKKGSG) covalently linked to β-galactosidase in order to demonstrate the capacity of NrTP for intracellular delivery of large molecules. NrTP6/β-galactosidase conjugates, prepared by maleimide-based chemistry, were stable and enzymatically active on the standard 4-methylumbelliferyl β-D-galactopyranoside substrate. Their translocation into HeLa cells, monitored by β-galactosidase activity as a readout of the uptake, showed efficient cellular entry and thus demonstrated the potential of NrTPs for intracellular delivery of large-size cargos with preservation of biological activity.engjournal article