Thiol-Reactive Dyes

MTSET (2-(Trimethylammonium)ethyl methanethiosulfonate, bromide) is a positively charged MTS reagent.

The thiol-reactive quencher, CFQ520 maleimide, has a broad and intense absorption (approximately 520 nm) but no fluorescence, making it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications.

NFQ1, a non-fluorescent quencher, is used for a new type of 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.

Eosin-5-maleimide is a good photosensitizer and can be used to selectively label thiols. It has a quantum yield of 0.

CPM is a widely used blue fluorescent thiol-reactive dye that is essentially nonfluorescent until it reacts with thiols, making it possible to quantify thiols without a separation step.

Fluorescein-5-maleimide is the most widely used green fluorescent thiol-reactive dye. The reaction requires very mild conditions and is highly specific.

INA (5-iodonaphthyl-1-azide) is a lipophilic photoreactive probe, which has been used to selectively label membrane-embedded cysteine residues of proteins.

CF® dye MTS are fast-reacting, highly selective thiol-reactive derivatives for reversible labeling of thiol groups with fluorescent CF® dyes.

TS biotin ethylenediamine (Biotin ethylenediamine thiosulfate, sodium salt) is a highly selective thiol labeling probe. Similar to the MTS group, TS (thiosulfate) group is capable of reacting with thiols at nearly neutral pH.