How can scientists visualize the purification of GFP post-SDS-PAGE?

Using fluorescence imaging is an effective method for visualizing the purification of GFP post-SDS-PAGE because GFP emits a bright green fluorescence when exposed to ultraviolet (UV) light. This unique property of GFP allows scientists to directly observe the protein even at low concentrations, making it easier to assess the presence and purity of the protein after electrophoresis.

In contrast to other staining methods like Coomassie staining, which visualize total protein content without highlighting specific proteins, fluorescence imaging directly targets the GFP, showcasing its distinct fluorescence. This specificity is particularly advantageous in experiments where the goal is to identify and quantify GFP amid a complex mixture of proteins.

While UV light exposure can generate fluorescence, it is not the technique used to visualize the protein directly; instead, fluorescence imaging is the established method to capture that emitted fluorescence in a usable format. Phosphorimaging, on the other hand, is typically used for radiolabeled substances and is less relevant in the context of GFP visualization after SDS-PAGE. Thus, fluorescence imaging stands out as the optimal choice for this application.