After centrifugation, does the eluate containing red fluorescent protein appear brighter or dimmer than the original cell lysate?

After centrifugation, does the eluate containing red fluorescent protein appear brighter or dimmer than the original cell lysate?

• A. Eluate is dimmer than the cell lysate.
• B. Eluate has the same brightness as the cell lysate.
• C. Eluate is slightly brighter than the cell lysate.
• D. Eluate is brighter than the cell lysate.

Answer: (D)

Brightness reflects how much red fluorescent protein is present in the measured sample. After purification, the eluate is enriched for the red fluorescent protein and many other cellular proteins and background materials are removed. With the same instrument settings, a higher concentration of the fluorescent protein in the eluate produces more emitted light, so it appears brighter than the original cell lysate. The lysate contains a lot of other proteins and possibly background fluorescence that dilute or obscure the signal, making it look dimmer by comparison. So, in typical purification conditions, the eluate will be brighter than the cell lysate.

Brightness reflects how much red fluorescent protein is present in the measured sample. After purification, the eluate is enriched for the red fluorescent protein and many other cellular proteins and background materials are removed. With the same instrument settings, a higher concentration of the fluorescent protein in the eluate produces more emitted light, so it appears brighter than the original cell lysate. The lysate contains a lot of other proteins and possibly background fluorescence that dilute or obscure the signal, making it look dimmer by comparison. So, in typical purification conditions, the eluate will be brighter than the cell lysate.