Practice: Detecting Proteins

You are working in a research lab studying a novel protein called WIZE. You have two versions of the protein, WIZE-14, which has incorporated light nitrogen, N14 and WIZE-15, which has incorporated heavy nitrogen, N15. Otherwise, they are exactly the same with the same folding structure and biological activity. One morning, you come into the lab and realize that you accidentally forgot to label your tubes last night. Whoops! What is the best technique to determine which tube has WIZE-14 and which tube has WIZE-15?
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