Activated esters (bifunctional)

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.

3-Maleimidopropionic acid NHS-ester

Bifunctional crosslinker with an amine-reactive succinimidyl ester and a thiol-reactive maleimide group.
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Cat. # Quantity Price Lead time
3419-100mg 100 mg –   in stock
3419-500mg 500 mg $110 in stock
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Alkyne-PEG2-NHS ester

Bifunctional hydrophilic linker with NHS ester and terminal alkyne functional group based on diethyleneglycol (PEG2).
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Cat. # Quantity Price Lead time
2219-1g 1 g $450 in stock
2219-5g 5 g $980 in stock
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Alkyne-PEG3-NHS ester

Bifunctional hydrophilic linker with NHS ester and terminal alkyne functional group based on triethyleneglycol (PEG3).
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Cat. # Quantity Price Lead time
2298-1g 1 g $490 in stock
2298-5g 5 g $980 in stock
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Alkyne-PEG4-NHS ester

Bifunctional hydrophilic linker with NHS ester and terminal alkyne functional group based on tetraethyleneglycol (PEG4).
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Cat. # Quantity Price Lead time
2409-100mg 100 mg $250 in stock
2409-1g 1 g $790 in stock
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ATFB SE (N-Succinimidyl 4-Azidotetrafluorobenzoate)

N-Succinimidyl 4-Azidotetrafluorobenzoate (ATFB SE, ATFB-OSu) is a photo-activatable linker used as a versatile labeling agent for investigating biological receptors.
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Cat. # Quantity Price Lead time
2574-250mg 250 mg $146 12 days
2574-1g 1 g $420 21 days
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Azide-PEG6-NHS ester

A hydrophilic bifunctional linker with azide and NHS ester function groups flanking PEG6 (hexaethylene glycol).
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Cat. # Quantity Price Lead time
3692-250mg 250 mg $325 in stock
3692-1g 1 g $539 in stock
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Azidobutyric acid NHS ester

Activated NHS ester for azido-labeling of peptides and proteins.
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Cat. # Quantity Price Lead time
53720 50 mg $110 in stock
63720 100 mg $210 in stock
73720 1 g $950 in stock
83720 5 g please inquire in stock
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Biotin-PEG4-NHS ester

PEG4-containing activated ester for simple and efficient biotin labeling of antibodies, proteins, and other primary amine-containing biomolecules.
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Cat. # Quantity Price Lead time
2893-100mg 100 mg $145 in stock
2893-1g 1 g $590 in stock
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Biotin-XX-NHS ester

Biotin derivative with long spacer to reduce steric effect when binding amino acids, peptides, or proteins by reacting with primary amines.
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Cat. # Quantity Price Lead time
2897-100mg 100 mg $225 in stock
2897-1g 1 g $670 in stock
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DBCO-NHS ester

Azodibenzocyclooctyne (DBCO, ADIBO) reagent for strain-promoted copper-free click chemistry (SPAAC). The reagent contains an NHS ester function for the attachment of the cyclooctyne to various molecules.
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Cat. # Quantity Price Lead time
34720 10 mg $80 in stock
44720 25 mg $110 in stock
54720 50 mg $135 in stock
64720 100 mg $210 in stock
94720 1 g $1000 in stock
K4720 5 g $3570 in stock
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DBCO-PEG6-NHS ester

A heterobifunctional linker with DBCO and NHS ester function groups flanking PEG6 (hexaethylene glycol).
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Cat. # Quantity Price Lead time
3664-10mg 10 mg –   in stock
3664-50mg 50 mg $247 in stock
3664-100mg 100 mg $449 in stock
3664-1g 1 g $3490 5 days
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DBCO-STP ester

Activated ester for modification of proteins/antibodies/peptides followed by introduction into copper-free click chemistry reaction.
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Cat. # Quantity Price Lead time
2584-5mg 5 mg –   in stock
2584-10mg 10 mg $90 in stock
2584-25mg 25 mg $180 in stock
2584-100mg 100 mg $450 in stock
2584-500mg 500 mg $1700 5 days
2584-1g 1 g $3000 in stock
2584-5g 5 g please inquire in stock
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Disuccinimidyl glutarate (DSG)

Homobifunctional crosslinker with two NHS ester groups at each end of a short 5-atom (7.7 angstrom) spacer.
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Cat. # Quantity Price Lead time
4018-100mg 100 mg $95 in stock
4018-1g 1 g $410 in stock
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Exo-BCN-PNP

BCN-PNP carbonate is a tool to introduce BCN moety via carbamate linkage with primary amino groups of substrate.
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Cat. # Quantity Price Lead time
4043-100mg 100 mg $280 in stock
4043-500mg 500 mg $990 in stock
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Hexynoic acid NHS ester

Hexynoic acid NHS ester for the labeling of biomolecules with alkyne group for copper-catalyzed click chemistry.
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Cat. # Quantity Price Lead time
41720 25 mg $95 in stock
51720 50 mg $180 in stock
61720 100 mg $290 in stock
91720 1 g please inquire in stock
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Hexynoic acid STP ester

Alkyne activated ester for the modification of amine groups. STP ester group is an excellent alternative to NHS ester functionality.
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Cat. # Quantity Price Lead time
569-25mg 25 mg $95 in stock
569-100mg 100 mg $185 in stock
569-500mg 500 mg $850 in stock
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Pentynoic acid STP ester

An activated ester for the introduction of alkyne into peptides/proteins and click reaction.
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Cat. # Quantity Price Lead time
30720 10 mg $110 in stock
40720 25 mg $210 in stock
50720 50 mg $410 in stock
60720 100 mg $595 5 days
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TCO-PEG4-NHS ester (axial isomer)

A heterobifunctional linker with trans-cyclooctene and NHS ester groups flanking PEG4 (tetraethylene glycol) for labeling of antibodies, proteins, and other primary amine-containing biomolecules.
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Cat. # Quantity Price Lead time
3056-10mg 10 mg $145 in stock
3056-25mg 25 mg $225 in stock
3056-100mg 100 mg $550 in stock