What evidence confirms the successful isolation and purification of GFP?

The successful isolation and purification of GFP is confirmed primarily by observing green fluorescence under UV light. This distinctive fluorescence is a characteristic feature of GFP, which arises from its unique chromophore structure that fluoresces when excited by ultraviolet or blue light. The presence of this fluorescence indicates that GFP has been successfully extracted from the host organism and retained its functional properties.

While the absence of other proteins could suggest a degree of purification, the mere lack of other proteins does not guarantee that GFP is present or has been effectively isolated. Additionally, an increase in protein concentration may imply that a purification step was undertaken, but it does not confirm the identity of the protein being purified. A change in pH during purification processes can have effects on protein solubility or stability, but again, it does not specifically indicate the successful isolation of GFP. Therefore, the observation of green fluorescence is the most direct and definitive evidence of successful GFP isolation.