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. Author manuscript; available in PMC: 2013 Oct 17.
Published in final edited form as: Bioconjug Chem. 2012 Sep 25;23(10):2007–2013. doi: 10.1021/bc300052u

Figure 5.

Figure 5

Biotinylation reagents 24a and 24b used to “arm” Fc-Sec proteins 21–23. (A) SPAAC reaction of Fc-Sec protein 21 (5 µg/mL) with biotin azide 24a. Reactions were conducted at room temperature (3 h) then overnight (4 °C) in PBS, pH 7.4. (B) SPAAC reaction of 21 with 24a. Protein 21 was mixed with 10-, 50- and 100-fold excess 24a as described above and then incubated with FR(+) HeLa cells. The cells were stained with PE-coupled avidin and then analyzed by flow cytometry. The upper limit of biotinylation is defined as the mean fluorescence intensity (MFI) exhibited by 19. Biotinylation efficiency is expressed as 100 × (MFI25 / MFI19).