Thiol

Fluorescein-5-maleimide (N-(5-Fluoresceinyl)maleimide) is a fluorescent thiol-reactive dye (excitation: 494 nm, emission: 519 nm).

NBD-X acid is an environmentally sensitive fluorescent probe used to study biological polymers such as lipids and proteins, with a higher labelling yield than NBD and significantly reduced fluorescence intensity in aqueous solutions. NBD-X acid emits green to yellow fluorescence with excitation/absorption wavelengths of 465/535 nm.

Bromobimane (Monobromobimane) is a non-fluorescent substance, but reacts with thiols to produce a fluorescent product.Bromobimane is used as a probe, often in clinical medicine, to test for sulfide levels in blood.

5-IAF is a fluorescein derivative of indoleacetamide, a fluorescent probe that can be used to label proteins and others containing free thiols (cysteine side chains). 5-IAF can label the catalytic (alpha) subunit of dog kidney Na,K-ATPase.

TPE-MI (Tetraphenylethene maleimide) is an aggregation-induced luminescent agent that stains living cells, can be used to capture cysteines in exposed unfolded proteins, and detects protein damage after dihydroartemisinin studies of malaria parasites.

NBD-Cl (NBD chloride) is a nonfluorescent compound that becomes highly fluorescent after reaction with amino or thiol groups.

ABD-F (4-(Aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole) is a highly reactive fluorescent reagent for the detection and quantification of thiol groups in thiol-containing amino acids, proteins, and tissues with maximum excitation and emission wavelengths of 389 nm and 513 nm, respectively.

NIR dye-1 is a near-infrared (NIR) fluorescent dye which has absorption and emission in the NIR region while retaining an optically tunable hydroxyl group.

BODIPY-TS (also known as Thiol-green 2) is a highly efficient thiol-specific turn-on probe with a fast response. It incorporates a thiosulfonate scaffold as its thiol recognition unit. BODIPY-TS displays excellent selectivity, low detection limit, and quantitative reactivity towards thiols. Moreover, it exhibits low toxicity. Notably, BODIPY-TS exhibits excitation at 490 nm and emission at 515 nm.

Tetramethylrhodamine-6-maleimide, a sulfhydryl-specific fluorescent dye, covalently bonds with cysteine. This compound is utilized as a label for real-time detection of local protein movements in fully active Na+/K+-ATPase [1] [2].

CPM, a maleimide derivative, acts as a blue fluorescent thiol-reactive dye with excitation/emission maxima of 384/470 nm [1].

Dibromobimane, a thiol-selective fluorescent imaging agent, is used to crosslink cysteine- and homocysteine-containing peptides [1].

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].

BDP 630/650 maleimide, a fluorophore compatible with the Cyanine5 channel, is valuable for fluorescence lifetime measurements due to its extended excited state lifetime [1].

BADAN (6-Bromoacetyl-2-dimethylaminonaphthalene) serves as a fluorescent probe that is sensitive to polarity [1].

5MP-Fluorescein (compound 3e), a fluorescein dye derived from 5-Methylene pyrrolone (5MP), exemplifies a bioconjugation tool that is both highly thiol-specific and can be removed without a trace [1].

Naph-EA-mal (Thiol-green 1) is a highly efficient and rapid-response thiol fluorescence probe specifically designed for protein labeling and bioimaging applications. This compound provides ultrafast turn-on fluorescence upon interacting with thiols, allowing for thiol detection in live cells, protein thiol labeling, quantification of total thiol concentrations in cell lysates, and determination of reversible protein thiol oxidation in fixed cells. It has an excitation wavelength of 488 nM and an emission wavelength of 540 nM.

N-(9-Acridinyl)maleimide, a maleimide-type fluorescent thiol reagent, exhibits negligible inherent fluorescence; however, its conjugates with thiol compounds display pronounced blue fluorescence. This characteristic enables its use in the fluorometric analysis of cysteine and glutathione [1].

DCI-Br-3 serves as a swift and selective probe with high sensitivity for thiol monitoring in the epileptic brain, exhibiting an excitation wavelength (λex) of 537 nm and an emission wavelength (λem) of 675 nm. It is also capable of efficiently penetrating the blood-brain barrier (BBB) [1].

N-(3-Fluoranthyl)maleimide, a thiol fluorescent probe with a lifetime of 20 nsec, has a maximum excitation wavelength of 370 nm and is suitable for studying time-dependent processes of biopolymers [1].

N-4-(5,6-Dimethoxy-N-phthalimidinyl)phenylmaleimide serves as a fluorescence reagent specifically for thiol labeling [1].

Cyanine3 maleimide tetrafluoroborate is a specialized labeling reagent targeting sulfhydryl groups, characterized by an excitation wavelength (λ ex) of 550 nm and an emission wavelength (λ em) of 580 nm. It is applicable in the labeling of proteins and peptides [1] [2].

NIR-Thiol dinitrobenzenesulfonate exhibits absorption and emission in the NIR region and is capable of imaging endogenously produced thiol in living cells and mice.

Acrylodan, when subjected to thiol reactions, exhibits sensitivity to the dipolarity and dynamics of its surrounding binding pocket, specifically those surrounding Cys 34.