NFQ1, a non-fluorescent quencher (absorption wavelength: 474 nm), is used for a new type of One Sample Fluorescence Resonance Energy Transfer (OS-FRET) method, enabling measurement of unquenched donor emission in the same sample. NFQ1 shows a broad absorption spectrum, ensuring its utility as a dark acceptor for many donors [1].

NFQ1 is used for the One Sample Fluorescence Resonance Energy Transfer (OS-FRET) method, employing a novel, non-fluorescent methanethiosulfonate-linked acceptor that can be reversibly coupled to a target sulfhydryl residue via a disulfide bond. After quantitating the quenched donor emission, the acceptor is removed by reduction, enabling measurement of unquenched donor emission in the same sample [1].