Figure 1.

A. Coumarin triazabutadiene 2 was synthesized from the corresponding aryl azide, 3. B. and C. are scans from SDS-PAGE gels. Fluor. = fluorescence scan; Coom. = coomassie blue staining. B. Bovine serum albumin (BSA) labeled with 2 (0.2 mM) in 100 mM PBS buffer with increasing pH (4, 5, 6, 7 and 8) for 12 hours. At far right, resorcinol is added to trap diazonium ion intermediate and reduces fluorescence signal. The samples were then run on a gel and analyzed. C. Samples of BSA in 100 mM PBS (pH 7) are irradiated with 350 nm light for varying times. At far right, resorcinol is added to trap diazonium ion intermediate and reduces fluorescence signal. The samples were then run on a gel and analyzed.