As part of the LanthaScreen™ TR-FRET Toolbox of assay reagents, LanthaScreen™ Reactive Terbium Chelate Labeling Reagents are available. The amine-reactive, isothiocyanate group conjugates to virtually any peptide or protein that contains one or more accessible amine moieties, such as the amine group found on a lysine residue or an unmodified N-terminal amine group of a peptide or protein. Amine-modified DNA oligonucleotides can be labeled as well. The thiol-reactive maleimide group can be conjugated to virtually any peptide or protein that contains one or more accessible thiol moieties, such as the thiol group found on a cysteine residue. Energy transfer to a suitable acceptor, such as fluorescein or rhodamine, is readily detected by monitoring an increase in acceptor fluorescence intensity.

See the user guide supplied with these reagents for applications-based protocols for labeling peptides containing free amino groups, amine-modified oligonucleotides, IgG antibodies, and cysteine-containing peptides or proteins.