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

BDP 558/568 maleimide is a boron-dipyrromethene (BODIPY) dye that contains a terminal maleimide group.

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].

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.

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

N-(9-Acridinyl)maleimide is a maleimide-type fluorescent thiol probe that emits blue fluorescence upon thiol conjugation, with an excitation wavelength of 355 nm and emission wavelength of 465 nm. It can be used for detecting cysteine and glutathione.

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

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.

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].

JUN00887, also known as BP Fluor 594 C5 Maleimide, is a bright red fluorescent dye with excellent water solubility and pH stability between pH 4 and pH 10. Its absorption and emission peaks are at 590 nm and 617 nm, respectively.

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].

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].

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

IRDye 800CW, Maleimide is a near-infrared (NIR) fluorescent dye that features a maleimide reactive group, enabling it to conjugate via thiol reactivity. It is ideal for use in live cell imaging.

IA-alkyne(Pr) is a clickable probe featuring thiol reactivity, suitable for studying protein-protein interactions.