Ethidium Bromide Titration with Herring DNA

Prepare an ethidium bromide solution (50 pM) in a fluorescence cuvette and then plot both absorption and emission spectra (Xex = 470 nm). The molar extinction coefficient of ethidium bromide at 480 nm is 5680 M-1 cm-1. 

To the fluorophore solution, add 8-9 pM DNA aliquots, and after each addition plot both absorption and emission spectra. The experiment will end after 18 DNA additions. 

Take two photos, one of ethidium bromide before adding DNA solution, the second at the end of the experiment. 

1 What are the indications showing that ethidium bromide is binding to DNA  

2 Compare the spectra obtained with those you find from the literature. 

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