What color indicates the presence of GFP in the supernatant?

The presence of Green Fluorescent Protein (GFP) in the supernatant is indicated by a glowing green color. This distinctive green fluorescence is due to the unique chromophore structure of GFP, which absorbs ultraviolet or blue light and re-emits it in the green spectrum. When you observe this glowing green color, it confirms that GFP is successfully present and has been released into the supernatant during the purification process. This characteristic fluorescence is a critical feature that researchers utilize to monitor the expression and purification of GFP-tagged proteins. Other colors, such as colorless, white, or bright yellow, do not correspond with the fluorescence characteristic of GFP and would point to the absence of the protein or the presence of different substances.