Synthetic peptides can be labelled with just about any molecule you like, and since the labelling can be done during synthesis, it is site specific. Another difference compared to labelling proteins and antibodies is that, simply due to the size difference, the amounts of labelling reagent required are much larger. Thus, there is a lot to gain by using comparatively less expensive reagents, such 5-FAM, TAMRA, and Biotin, while maintaining the high standards of every other aspect of the production.
FRET is an example of an application that uses two labels. Förster (Fluorescence) Resonance Energy Transfer, is a non-radiative energy transfer between two chromophores (not necessarily fluorescent). The interaction is highly distance dependent and suitable for researching phenomena that are manifested in changes in close (molecular) proximity. Depending on the detection technique employed, a donor-acceptor pair can be two different chromophores or the same, either be fluorescent or not. Using a fluorescent donor and a non-fluorescent acceptor has the advantage of eliminating background fluorescence due to direct acceptor excitation.
A note of consideration; When constructing synthetic peptides incorporating dyes, the choice of location for the molecule may have an impact on background signal. Due to the fact that peptides are synthesized from C-terminus to N-terminus, and depending on synthesis strategy, one can ensure that only peptides of full length carry the dye when it is attached to the N-terminus. Conversely, when the dye is attached to the C-terminus, all peptide molecules will carry the label.
Innovagen has serviced the research community since 1992. Over the years we have been providing synthetic peptides with various labels (Biotin, Dabcyl, DOTA, FAM, TAMRA, etc.), and we know how just choosing the right synthesis strategy can make a world of difference for the final product. But our commitment goes beyond this as we believe that quality always pays off and we will go that extra mile for the benefit of your project. Please take a few moments to read about our view on production and quality control.
Examples of references of customers using our custom peptide synthesis services for the production of labelled peptides include;
E. Andersson Nordahl, V. Rydengård, P. Nyberg, D. P. Nitsche, M. Mörgelin, M. Malmsten, L. Björck & A. Schmidtchen.
Activation of the complement system generates antibacterial peptides
PNAS November 30, 2004 vol. 101 no. 48 16879-16884
H.L. Åmand, H. A. Rydberg, L. H. Fornander, P. Lincoln, B. Nordén, E. K. Esbjörner.
Cell surface binding and uptake of arginine- and lysine-rich penetratin peptides in absence and presence of proteoglycans.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 15 June 2012, ISSN 0005-2736
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