Activated esters

Primary or secondary amino groups are ubiquitous in biomolecules. They are present in proteins and peptides as ε-amino groups of lysines and N-terminal amino groups. Many natural and synthetic small molecules are amines, and DNAs with amino groups can be prepared by solid phase synthesis, and enzymatically.

Amino groups can be modified by acylation with various activated carbonyl compounds. Among these compounds, activated N-hydroxysuccinimide esters are most suitable for biolabeling and bioconjugation applications.

NHS ester coupling chemistry

Compared to other activated esters, NHS derivatives possess good stability in aqueous environment. Optimal pH for the coupling of amines with NHS esters in aqueous buffers is 8.3-8.5. Labeling is also possible in organic solvents. Polar aprotic solents, such as DMF or DMSO, are preferred. One equivalent of tertiary amine base, such as triethylamine, or diisopropylethylamine (DIPEA) is necessary to achieve efficient amine acylation in non-aqueous solution.

AF 343 (Coumarin) X NHS ester

AF 343 (Coumarin) is a blue emitting dye that can serve as a FRET donor for fluorescein (FAM). This structure features a linker between Coumarin 343 fluorophore, and the functional group. It provides better solubility, and spatial separation between the dye, and the functional group.
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Cat. # Quantity Price Lead time
12620 1 mg $110 in stock
22620 5 mg $210 in stock
42620 25 mg $410 in stock
52620 50 mg $695 in stock
62620 100 mg $1190 in stock
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AF 430 NHS ester

AF 430 is a hydrophilic coumarin dye with emission in the green-yellow range. The NHS ester is used for the labeling of amine groups.
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Cat. # Quantity Price Lead time
10820 1 mg $110 in stock
20820 5 mg $165 in stock
40820 25 mg $380 in stock
50820 50 mg $695 in stock
60820 100 mg $1190 in stock
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AF 488 NHS ester

AF 488 NHS ester, a bright, photostable, and hydrophilic fluorescent dye for the green channel.
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Cat. # Quantity Price Lead time
11820 1 mg $125 in stock
21820 5 mg $325 in stock
31820 10 mg $480 in stock
41820 25 mg $950 in stock
51820 50 mg $1625 in stock
61820 100 mg $2090 in stock
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AF 488 TFP ester

Tetrafluorophenyl ester of green fluorescent dye AF 488 for labeling amino groups in proteins, peptides, and modified oligonucleotides.
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Cat. # Quantity Price Lead time
118T0 1 mg $165 in stock
218T0 5 mg $510 in stock
418T0 25 mg $1650 in stock
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AF 532 NHS ester

NHS-ester of AF 532 dye for protein, peptide, and modified oligonucleotide labeling via reaction with amino groups.
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Cat. # Quantity Price Lead time
1C820 1 mg $140 in stock
2C820 5 mg $450 in stock
4C820 25 mg $1460 in stock
5C820 50 mg $1890 in stock
6C820 100 mg $2640 in stock
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AF 555 NHS ester

AF 555 NHS ester, a bright, photostable, and hydrophilic fluorescent dye for the yellow channel.
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Cat. # Quantity Price Lead time
1K820 1 mg $140 in stock
2K820 5 mg $450 in stock
4K820 25 mg $1460 in stock
5K820 50 mg $1890 in stock
6K820 100 mg $2640 in stock
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AF 568 NHS ester

AF 568 derivative for labeling proteins and other high- and low-molecular weight ligands with free amines.
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Cat. # Quantity Price Lead time
14820 1 mg $125 in stock
24820 5 mg $325 in stock
44820 25 mg $720 in stock
54820 50 mg $1325 in stock
64820 100 mg $2090 in stock
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AF 594 NHS ester

Red-fluorescent NHS-ester of AF 594 dye for labeling proteins, peptides, antibodies, and any molecules containing an -NH2 group. Pure 5-isomer
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Cat. # Quantity Price Lead time
2825-1mg 1 mg $125 5 days
2825-5mg 5 mg $425 in stock
2825-25mg 25 mg $1240 in stock
2825-50mg 50 mg $1890 in stock
2825-100mg 100 mg $2640 in stock
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AF 647 NHS ester

Bright, water-soluble succinimide ester of AF 647 dye for protein and antibody labeling.
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Cat. # Quantity Price Lead time
16820 1 mg $140 in stock
26820 5 mg $450 in stock
46820 25 mg $1460 in stock
56820 50 mg $1890 in stock
66820 100 mg $2640 in stock
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AMCA NHS ester

NHS-ester of AMCA dye for protein, peptide, and modified oligonucleotide labeling via reaction with amino groups. AMCA is one of the brightest blue fluorescent dyes with large Stoke's shift and high resistance to photobleaching.
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Cat. # Quantity Price Lead time
3606-5mg 5 mg $110 in stock
3606-25mg 25 mg $290 in stock
3606-50mg 50 mg $435 in stock
3606-100mg 100 mg $595 in stock
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BDP 558/568 NHS ester

BDP 558/568 is a fluorophore for the yellow region of the spectrum. Like other BDP dyes, this fluorophore has high fluorescence quantum yield, brightness, and photostability.
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Cat. # Quantity Price Lead time
17420 1 mg $125 in stock
27420 5 mg $260 in stock
47420 25 mg $510 in stock
57420 50 mg $895 in stock
67420 100 mg $1490 in stock
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BDP 564/570 NHS ester

Lypohilic borodipyrromethene dye with orange emission for the labeling of primary and secondary amine groups.
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Cat. # Quantity Price Lead time
1H420 1 mg $125 in stock
2H420 5 mg $325 in stock
4H420 25 mg $510 in stock
5H420 50 mg $895 in stock
6H420 100 mg $1490 in stock
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BDP 576/589 NHS ester

BDP 576/589 NHS ester is a bright hydrophobic dye with emission in the orange spectrum range. It can be used in fluorescence anisotropy assays.
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Cat. # Quantity Price Lead time
1G420 1 mg $125 in stock
2G420 5 mg $260 in stock
4G420 25 mg $510 in stock
5G420 50 mg $895 in stock
6G420 100 mg $1490 in stock
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BDP 581/591 NHS ester

NHS ester derivative of BDP 581/591 borondipyrromethene fluorophore for the labeling of proteins, peptides, and other biomolecules. The dye is useful for fluorescence polarization and two-photon experiments, and as a ROS probe.
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Cat. # Quantity Price Lead time
16420 1 mg $125 in stock
26420 5 mg $260 in stock
46420 25 mg $510 in stock
56420 50 mg $895 in stock
66420 100 mg $1490 in stock
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BDP 630/650 X NHS ester

BDP 630/650 is a borondipyrromethene fluorophore tuned to Cyanine5 excitation and emission channels. The dye is bright and highly photostable. It is useful for fluorescence polarization assays. This is an amine-reactive NHS ester derivative.
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Cat. # Quantity Price Lead time
15420 1 mg $125 5 days
25420 5 mg $260 in stock
45420 25 mg $510 in stock
55420 50 mg $895 in stock
65420 100 mg $1490 in stock
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BDP 650/665 X NHS ester

Amine reactive of BDP 650/665, a borondipyrromethene dye for Cy5 channel, possessing a high molar extinction coefficient, and a good emission quantum yield.
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Cat. # Quantity Price Lead time
1E420 1 mg $125 in stock
2E420 5 mg $260 in stock
4E420 25 mg $510 in stock
5E420 50 mg $895 in stock
6E420 100 mg $1490 in stock
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BDPep FL NHS ester

BDP FL analog derivative suitable for solid phase synthesis SPPS.
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Cat. # Quantity Price Lead time
1J420 1 mg –   in stock
2J420 5 mg $260 in stock
4J420 25 mg $510 in stock
5J420 50 mg $895 in stock
6J420 100 mg $1490 in stock
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BDP FL NHS ester

Amino-reactive BDP FL, a very bright and photostable dye for fluorescein channel.
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Cat. # Quantity Price Lead time
11420 1 mg $125 $98 in stock
21420 5 mg $260 $175 in stock
41420 25 mg $485 in stock
51420 50 mg $824 in stock
61420 100 mg $1380 in stock
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BDP R6G NHS ester

BDP R6G is a borondipyrromethene dye which has absorption and emission spectra similar to R6G.
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Cat. # Quantity Price Lead time
14420 1 mg $125 in stock
24420 5 mg $260 in stock
44420 25 mg $510 in stock
54420 50 mg $895 in stock
64420 100 mg $1490 in stock
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BDP TMR NHS ester

Amine reactive NHS ester of BDP TMR, bright borondipyrromethene dye for TAMRA channel especially suitable for fluorescence polarization assays.
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Cat. # Quantity Price Lead time
12420 1 mg $125 in stock
22420 5 mg $260 in stock
42420 25 mg $510 in stock
52420 50 mg $895 in stock
62420 100 mg $1490 in stock
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BDP TMR X NHS ester

Amine reactive NHS ester of BDP TMR, bright borondipyrromethene dye for TAMRA channel especially suitable for fluorescence polarization assays. This compound contains an aminohexanoic acid (C6) linker between the dye and the functional group.
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Cat. # Quantity Price Lead time
1F420 1 mg $125 in stock
2F420 5 mg $260 in stock
4F420 25 mg $510 in stock
5F420 50 mg $895 in stock
6F420 100 mg $1490 in stock
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BDP TR X NHS ester

BDP TR X NHS ester is a derivative of BDP TR containing a long linker based on aminohexanoic acid (C6). The dye has absorption and emission close to ROX. The NHS ester function can be used to conjugate proteins and peptides.
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Cat. # Quantity Price Lead time
1D420 1 mg $125 in stock
2D420 5 mg $325 in stock
4D420 25 mg $510 in stock
5D420 50 mg $895 in stock
6D420 100 mg $1490 in stock
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Cyanine3.5 NHS ester

Cyanine3.5 dye NHS ester derivative the labeling of amino-groups in biomolecules.
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Cat. # Quantity Price Lead time
12020 1 mg $125 in stock
22020 5 mg $260 in stock
42020 25 mg $510 in stock
52020 50 mg $895 in stock
62020 100 mg $1490 in stock
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Cyanine3B NHS ester

Cyanine3B NHS ester is a reactive dye with significantly increased fluorescence quantum yield and photostability for the specific labeling of amino-groups in biomolecules.
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Cat. # Quantity Price Lead time
19320 1 mg $140 in stock
29320 5 mg $340 in stock
49320 25 mg $990 in stock
59320 50 mg $1690 in stock
69320 100 mg $3100 in stock
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Cyanine3 NHS ester

Amine-reactive Cyanine3 dye NHS ester for the labeling of amino-groups.
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Cat. # Quantity Price Lead time
11020 1 mg $91 in stock
21020 5 mg $119 in stock
41020 25 mg $380 in stock
51020 50 mg $670 in stock
61020 100 mg $1150 in stock
81020 1 g please inquire 12 days
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Cyanine5.5 NHS ester

Cyanine5.5 NHS is far-red / near-infrared amine-reactive dye.
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Cat. # Quantity Price Lead time
17020 1 mg $125 in stock
27020 5 mg $260 in stock
47020 25 mg $510 in stock
57020 50 mg $895 in stock
67020 100 mg $1490 in stock
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Cyanine5 NHS ester

Amine-reactive Cyanine5 activated ester for the labeling of proteins, peptides, and other molecules.
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Cat. # Quantity Price Lead time
13020 1 mg $87 in stock
23020 5 mg $117 in stock
43020 25 mg $337 in stock
53020 50 mg $550 in stock
63020 100 mg $870 in stock
83020 1 g please inquire 12 days
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Cyanine7.5 NHS ester

Amine reactive NHS ester of NIR fluorescent dye Cyanine7.5 .
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Cat. # Quantity Price Lead time
16020 1 mg $125 in stock
26020 5 mg $260 in stock
46020 25 mg $510 in stock
56020 50 mg $895 in stock
66020 100 mg $1490 in stock
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Cyanine7 NHS ester

Amine reactive NHS ester of near infrared dye Cyanine7.
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Cat. # Quantity Price Lead time
15020 1 mg $125 in stock
25020 5 mg $260 in stock
45020 25 mg $510 in stock
55020 50 mg $895 in stock
65020 100 mg $1490 in stock
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DusQ 1 NHS ester

Functionalized DusQ 1 quencher derivative with quenching range from 480 - 580 nm for labeling of amine-containing molecules.
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Cat. # Quantity Price Lead time
21D20 5 mg –   in stock
41D20 25 mg $315 in stock
51D20 50 mg $580 in stock
61D20 100 mg $885 in stock
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DusQ 21 NHS ester

Amino-reactive NHS ester with quencher for the conjugation with amines-containing molecules, DusQ 21 quenching range 590 - 720 nm.
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Cat. # Quantity Price Lead time
28D20 5 mg –   in stock
48D20 25 mg $315 in stock
68D20 100 mg $885 in stock
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DusQ 2 NHS ester

DusQ 2 dark quencher with a quenching range from 560 - 670 nm with primary amine reactivity for synthesis of FRET probes. This NHS ester can be coupled to various molecules bearing amino groups.
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Cat. # Quantity Price Lead time
22D20 5 mg –   in stock
42D20 25 mg $315 in stock
52D20 50 mg $580 in stock
62D20 100 mg $885 in stock
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DusQ 3 NHS ester

Amino-reactive NHS ester for the labeling with far-red quencher DusQ 3.
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Cat. # Quantity Price Lead time
23D20 5 mg –   in stock
43D20 25 mg $315 in stock
53D20 50 mg $580 in stock
63D20 100 mg $885 in stock
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FAM isothiocyanate (FITC), 5- and 6-isomers

An isothiocyanate derivative of fluorescein for labeling of antibodies and other biomolecules. Mix of 5- and 6-isomers.
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Cat. # Quantity Price Lead time
3524-100mg 100 mg –   in stock
3524-500mg 500 mg $249 in stock
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FAM NHS ester, 6-isomer

Activated N-hydroxysuccinimide ester of fluorescein (FAM), pure 6-isomer.
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Cat. # Quantity Price Lead time
15120 1 mg –   in stock
25120 5 mg $110 in stock
45120 25 mg $145 in stock
55120 50 mg $260 in stock
65120 100 mg $470 in stock
85120 1 g please inquire in stock
95120 5 g please inquire in stock
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HEX NHS ester, 6-isomer

NHS-ester of HEX dye for proteins, peptides, and modified oligonucleotides labeling via reaction with amino groups.
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Cat. # Quantity Price Lead time
2B220 5 mg $175 in stock
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JOE NHS ester, 5-isomer

JOE is a fluorescent dye with emission in the yellow part of the spectrum. This derivative is an activated NHS ester for conjugation with amines.
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Cat. # Quantity Price Lead time
11120 1 mg $110 in stock
21120 5 mg $210 in stock
41120 25 mg $410 in stock
51120 50 mg $695 in stock
61120 100 mg $1190 in stock
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Pyrenebutyric acid NHS ester

Pyrene NHS ester for the labeling of biomolecules with pyrene residue. Pyrene is a fluorescent proximity probe which forms excimers, and it is also an anchor group for graphite immobilization.
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Cat. # Quantity Price Lead time
63520 100 mg $110 in stock
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R6G NHS ester, 5-isomer

R6G (rhodamine 6G) NHS ester, pure 5-isomer. This dye is often used for the labeling of oligonucleotides for qPCR.
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Cat. # Quantity Price Lead time
14220 1 mg $110 5 days
24220 5 mg $210 in stock
44220 25 mg $410 in stock
54220 50 mg $695 in stock
64220 100 mg $1190 in stock
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ROX NHS ester, 5-isomer

Activated NHS ester of ROX (rhodamine X or rhodamine 101), pure 5-isomer, for the labeling of amine groups of biomolecules.
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Cat. # Quantity Price Lead time
11220 1 mg $110 in stock
21220 5 mg $210 in stock
41220 25 mg $410 in stock
51220 50 mg $695 in stock
61220 100 mg $1190 in stock
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ROX NHS ester, 6-isomer

Pure 6-isomer of ROX (Rhodamine X, R101) NHS-ester for amine labeling.
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Cat. # Quantity Price Lead time
12220 1 mg $110 in stock
22220 5 mg $210 in stock
42220 25 mg $410 in stock
52220 50 mg $695 in stock
62220 100 mg $1190 in stock
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sulfo-Cyanine3.5 NHS ester

Amine reactive activated ester of water soluble, sulfonated sulfo-Cyanine3.5 dye.
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Cat. # Quantity Price Lead time
12320 1 mg $125 5 days
22320 5 mg $325 in stock
42320 25 mg $850 in stock
52320 50 mg $1490 in stock
62320 100 mg $1990 in stock
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sulfo-Cyanine3 NHS ester

Water soluble sulfo-Cyanine3 SE activated ester for amino-biomolecule labeling.
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Cat. # Quantity Price Lead time
11320 1 mg $91 in stock
21320 5 mg $119 in stock
41320 25 mg $395 in stock
51320 50 mg $729 in stock
61320 100 mg $1290 in stock
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sulfo-Cyanine5.5 NHS ester

Water soluble, sulfonated, far-red sulfo-Cyanine5.5 dye in the form of NHS ester.
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Cat. # Quantity Price Lead time
17320 1 mg $125 in stock
27320 5 mg $325 in stock
47320 25 mg $850 in stock
57320 50 mg $1490 in stock
67320 100 mg $1990 in stock
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sulfo-Cyanine5 bis-NHS ester

Water soluble amine reactive Cyanine5 dye with two NHS ester groups.
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Cat. # Quantity Price Lead time
133D0 1 mg $125 in stock
233D0 5 mg $325 in stock
433D0 25 mg $850 in stock
533D0 50 mg $1490 in stock
633D0 100 mg $1990 in stock
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sulfo-Cyanine5 NHS ester

Water-soluble sulfo-Cyanine5 succinimidyl ester for labeling various amine-containing molecules in the aqueous phase.
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Cat. # Quantity Price Lead time
13320 1 mg $91 in stock
23320 5 mg $119 in stock
43320 25 mg $345 in stock
53320 50 mg $557 in stock
63320 100 mg $890 in stock
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sulfo-Cyanine7.5 NHS ester

A water-soluble near-infrared emitting dye for in vivo imaging applications. sulfo-Cyanine7.5 is an analog of indocyanine green (ICG) possessing higher emission quantum yield and a linker arm.
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Cat. # Quantity Price Lead time
16320 1 mg $125 in stock
26320 5 mg $325 in stock
46320 25 mg $850 in stock
56320 50 mg $1490 in stock
66320 100 mg $1990 in stock
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sulfo-Cyanine7 bis-NHS ester

sulfo-Cyanine7 bis-NHS ester is a bifunctional derivative of water-soluble near-infrared sulfo-Cyanine7. It contains two activated ester functional groups.
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Cat. # Quantity Price Lead time
153D0 1 mg $125 in stock
253D0 5 mg $325 in stock
453D0 25 mg $850 in stock
553D0 50 mg $1490 in stock
653D0 100 mg $1990 in stock
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sulfo-Cyanine7 NHS ester

sulfo-Cyanine7 NHS ester is a water-soluble, near-infrared, amine-reactive dye.
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Cat. # Quantity Price Lead time
15320 1 mg $125 in stock
25320 5 mg $325 in stock
45320 25 mg $850 in stock
55320 50 mg $1490 in stock
65320 100 mg $1990 in stock
Found better price? Let us know and we will propose the way forward!

TAMRA NHS ester, 5-isomer

Amine-reactive, activated N-hydroxysuccinimidyl ester of TAMRA dye for the labeling of amine groups of proteins, peptides, and amino-oligonucleotides. Pure 5-isomer.
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Cat. # Quantity Price Lead time
17120 1 mg –   in stock
27120 5 mg $210 in stock
47120 25 mg $350 in stock
57120 50 mg $595 in stock
67120 100 mg $790 in stock
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TAMRA NHS ester, 6-isomer

NHS-ester of TAMRA dye for proteins, peptides, and modified oligonucleotides labeling via reaction with amino groups. Pure 6-isomer.
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Cat. # Quantity Price Lead time
18120 1 mg $110 in stock
28120 5 mg $210 in stock
48120 25 mg $350 in stock
58120 50 mg $595 in stock
68120 100 mg $790 in stock
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Thiazole Orange NHS ester

Thiazole Orange NHS ester for labeling biomolecules (peptides, proteins, amino-DNA, etc.). Thiazole orange is a cyanine dye that is essentially dark in solution but has a bright fluorescence in double-stranded DNA and RNA.
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Cat. # Quantity Price Lead time
2183-1mg 1 mg –   in stock
2183-5mg 5 mg $60 in stock
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TR X NHS ester, 5-isomer

TR is a red-emitting fluorescent dye based on sulforhodamine scaffold, an amine-reactive NHS ester.
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Cat. # Quantity Price Lead time
1V220 1 mg $125 in stock
2V220 5 mg $325 in stock
4V220 25 mg $510 in stock
5V220 50 mg $895 in stock
6V220 100 mg $1490 in stock
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