Shop All Aldehyde-, Ketone-, & Carboxylate-Reactive Labels

ARP (N-(aminooxyacetyl)-N'-(D-Biotinoyl) hydrazine, Trifluoroacetic Acid Salt) (Invitrogen™)

ARP (Aldehyde-Reactive Probe) is a biotinylated hydroxylamine that reacts with the exposed aldehyde group formed at abasic sites in damaged DNA. The biotins bound to the abasic sites can then be quantitated with fluorescent or enzyme-conjugated streptavidin complexes. ARP is suitable for use in microplate assays.

NeutrAvidin™ Protein, Maleimide-Activated (Thermo Scientific™)

Thermo Scientific Maleimide-Activated NeutrAvidin Protein is a specially-prepared form of avidin that decreases background in biotin-binding.

Features of NeutrAvidin Protein:

Near-neutral isoelectric point—pI = 6.3, more neutral than native avidin
Nearly devoid of glycosylation—decreased possibility of lectin binding compared to native avidin
No RYD recognition sequence—no known off-target binding domains like streptavidin
Affordable—significantly less expensive than streptavidin

NeutrAvidin Protein is deglycosylated native avidin from egg whites. Removal of the excess carbohydrate by an exclusive process yields a protein with a more neutral isoelectric point and less nonspecific binding properties. Conjugated NeutrAvidin Protein provides exceptional performance in western blot, ELISA and IHC applications that require biotin-binding probes. Assay specificity, sensitivity, and signal-to-noise ratios with NeutrAvidin Protein are generally equivalent or better than with the significantly more expensive streptavidin.

Avidin is a glycoprotein found in the egg white and tissues of birds, reptiles and amphibia. The biotin-binding protein contains four identical subunits having a combined mass of 67,000-68,000 daltons. Removing the glycosylation from avidin yields NeutrAvidin Protein with a mass of 60,000 daltons. Carbohydrate-based lectin-binding is reduced to undetectable levels, yet biotin-binding affinity is retained. NeutrAvidin Protein offers the advantages of a neutral pI to minimize nonspecific adsorption, along with lysine residues that remain available for derivatization or other customized conjugation. NeutrAvidin Protein yields the lowest nonspecific binding among the known biotin binding proteins. The specific activity for biotin-binding is approximately 14 µg/mg of protein, which is near the theoretical maximum activity.

Related Products
NeutrAvidin™ Protein
NeutrAvidin™ Protein, Horseradish Peroxidase Conjugated
NeutrAvidin™ Protein, Alkaline Phosphatase Conjugated
NeutrAvidin™ Protein, Fluorescein Conjugated

EZ-Link™ Alkoxyamine-PEG12-Biotin (Thermo Scientific™)

Thermo Scientific EZ-Link Alkoxyamine-PEG12-Biotin is a biotinylation reagent containing a long, 12-unit polyethylene glycol (PEG) spacer for biotinylating macromolecules at carbohydrate groups that have been oxidized to form aldehydes.

Features of EZ-Link Alkoxyamine-PEG12-Biotin:

Glycoprotein labeling—biotinylate glycosylated proteins at sialic acid residues for detection or purification using streptavidin probes or resins
Cell surface labeling—biotinylate and isolate cell surface glycoproteins; reagent does not permeate membranes of whole cells
Aldehyde-reactive—reacts with aldehydes formed by periodate-oxidation of sugar groups
Alkoxyamine-activated—aminooxy group forms more stable linkages than hydrazide reagents
Pegylated—spacer arm contains a hydrophilic, 12-unit, polyethylene glycol (PEG) group
Enhances solubility—pegylation imparts water solubility to the biotinylated molecule, helping to prevent aggregation of biotinylated antibodies stored in solution
Irreversible—forms stable (permanent) oxime bonds; spacer arm cannot be cleaved
Solubility—usually dissolved in DMSO to make concentrated stock solution
Long reach—spacer arm (total length added to target) is 55.4 angstroms

Aminooxy-biotin reagents such as this one are useful for biotinylating glycoproteins and other molecules that have oxidizable polysaccharides groups. The alkoxyamine group (also called an aminooxy or aminoxy group) conjugates to aldehydes of oxidized sugars. EZ-Link Alkoxyamine-PEG-Biotin reagents contain a multi-functional extended spacer arm that is a flexible, non-immunogenic hydrophilic polyethylene glycol (PEG), which imparts water solubility to labeled molecules. Consequently, antibodies labeled with pegylated biotin reagents exhibit less aggregation when stored in solution compared to antibodies labeled with reagents having only hydrocarbon spacers.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

Biotinylation reagents differ in reactivity, length, solubility, cell permeability and cleavability. Hydrazides and alkoxyamines are two types of carbonyl-reactive groups. Alkoxyamines (—O-NH2) react specifically with aldehyde groups in near-neutral conditions to form stable oxime linkages. The reaction is more efficient in the presence of aniline (Part No. 88944). Alternatively, alkoxyamines can be conjugated to carboxylic acids using EDC carbodiimide chemistry.

Reactive aldehyde groups can be generated in glycoproteins and other polysaccharide compounds by oxidation of constituent sugar diols using sodium periodiate (Part No. 20504). Sialic acid residues are common components of protein glycosylation and are easily converted to aldehydes with 1 mM NaIO4.

APTS (8-Aminopyrene-1,3,6-Trisulfonic Acid, Trisodium Salt) (Invitrogen™)

The aromatic amine of APTS (8-aminopyrene-1,3,6-trisulfonic acid, trisodium salt) can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a stable amine derivative by sodium borohydride (NaBH4) or sodium cyanoborohydride (NaCNH3) to form new biotinylated probes.

Cascade Blue™ hydrazide, Trisodium Salt (Invitrogen™)

The cell-impermeant, fixable, polar tracer Cascade Blue® hydrazide can be used to investigate cell-cell and cell-liposome fusion as well as membrane permeability and transport through gap junctions or cell uptake during pinocytosis. This water-soluble tracer can be introduced into cells by whole-cell patch clamping, iontophoresis, osmotic lysis of pinocytic vesicles or comparable methods. Additionally, carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247).

EZ-Link™ Biotin-LC-Hydrazide (Thermo Scientific™)

Thermo Scientific EZ-Link Hydrazide-LC-Biotin is a mid-length, simple, hydrazide-activated biotinylation reagent for labeling glycoproteins and other carbohydrate-containing compounds having oxidizable sugars or aldehydes.

Features of EZ-Link Biotin-LC-Hydrazide:

Glycoprotein labeling—biotinylate glycosylated proteins at sialic acid residues for detection or purification using streptavidin probes or resins
Cell surface labeling—biotinylate and isolate cell surface glycoproteins
Aldehyde-reactive—reacts with aldehydes formed by periodate-oxidation of sugar groups
Hydrazide-activated—perform reactions at pH 4 to 6 in buffers such as sodium acetate
Irreversible—forms semi-permanent hydrazone bonds; spacer arm cannot be cleaved
Solubility—usually dissolved in DMSO before further dilution in aqueous buffers
Spacer arm length—24.7Å

This biotin hydrazide reagent enables simple and efficient biotin labeling of polyclonal antibodies and other glycoproteins. Mild oxidation of antibodies with sodium periodate produces reactive aldehydes on the carbohydrate moieties of the Fc portion that can be modified by hydrazides. This approach is advantageous for labeling antibodies because biotinylation occurs only at the sites of glycosylation, which are primarily in the Fc region of the antibody, far from the antigen binding site.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

Biotinylation reagents differ in reactivity, length, solubility, cell permeability and cleavability. Hydrazides and alkoxyamines are two types of carbonyl-reactive groups. Hydrazides (—NH-NH2) react specifically with aldehyde groups in slightly acidic conditions to form hydrazone linkages; these can be further reduced to stable secondary amine bonds using sodium cyanoborohydride (Part No. 44892). The reaction is more efficient in the presence of aniline (Part No. 88944). Alternatively, hydrazides can be conjugated to carboxylic acids using EDC carbodiimide chemistry.

Reactive aldehyde groups can be generated in glycoproteins and other polysaccharide compounds by oxidation of constituent sugar diols using sodium periodiate (Part No. 20504). Sialic acid residues are common components of protein glycosylation and are easily converted to aldehydes with 1 mM NaIO4.

Related Products
EZ-Link™ Hydrazide-Biotin

Qdot™ 625 ITK™ Carboxyl Quantum Dots (Invitrogen™)

Qdot® 625 ITK™ carboxyl quantum dots are the ideal starting material for preparing custom conjugates that require high loading of biomolecules. These materials are carboxylate functionalized and can be coupled to amine groups of proteins and modified oligonucleotides using EDC-mediated condensation. The coatings of these probes provides more binding sites than our Qdot® ITK™ amino quantum dots, but lacks PEG linkers that help to prevent non-specific interactions. These materials can be conjugated to X-PEG-amine bi-functional linkers for custom reactivity and higher specificity. Our Qdot® ITK™ carboxyl quantum dots are provided as 8 µM solutions and are available in all 9 Qdot® probe colors.

Important Features of Qdot® ITK™ Carboxyl Quantum Dots:
• Qdot® 625 ITK™ carboxyl quantum dot has emission maxima of ~625 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large Stokes shift
• Available in multiple colors
• Ideal for various labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the carboxyl-derivatized form, we offer Qdot® ITK™ quantum dots with amino and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Qdot™ 525 ITK™ Carboxyl Quantum Dots (Invitrogen™)

Qdot® 525 ITK™ carboxyl quantum dots are the ideal starting material for preparing custom conjugates that require high loading of biomolecules. These materials are carboxylate functionalized and can be coupled to amine groups of proteins and modified oligonucleotides using EDC-mediated condensation. The coatings of these probes provides more binding sites than our Qdot® ITK™ amino quantum dots, but lacks PEG linkers that help to prevent non-specific interactions. These materials can be conjugated to X-PEG-amine bi-functional linkers for custom reactivity and higher specificity. Our Qdot® ITK™ carboxyl quantum dots are provided as 8 µM solutions and are available in all 9 Qdot® probe colors.

Important Features of Qdot® ITK™ Carboxyl Quantum Dots:
• Qdot® 525 ITK™ carboxyl quantum dot has emission maxima of ~525 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large Stokes shift
• Available in multiple colors
• Ideal labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the carboxyl-derivatized form, we offer Qdot® ITK™ quantum dots with amino and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

EZ-Link™ Alkoxyamine-PEG4-Biotin (Thermo Scientific™)

Thermo Scientific EZ-Link Alkoxyamine-PEG4-Biotin is a biotinylation reagent containing a four-unit polyethylene glycol (PEG) spacer for biotinylating macromolecules at carbohydrate groups that have been oxidized to form aldehydes.

Features of EZ-Link Alkoxyamine-PEG4-Biotin:

Glycoprotein labeling—biotinylate glycosylated proteins at sialic acid residues for detection or purification using streptavidin probes or resins
Cell surface labeling—biotinylate and isolate cell surface glycoproteins; reagent does not permeate membranes of whole cells
Aldehyde-reactive—reacts with aldehydes formed by periodate-oxidation of sugar groups
Alkoxyamine-activated—aminooxy group forms more stable linkages than hydrazide reagents
Pegylated – spacer arm contains a hydrophilic, 4-unit, polyethylene glycol (PEG) group
Enhances solubility – pegylation imparts water solubility to the biotinylated molecule, helping to prevent aggregation of biotinylated antibodies stored in solution
Irreversible—forms stable (permanent) oxime bonds; spacer arm cannot be cleaved
Solubility—usually dissolved in DMSO to make concentrated stock solution
Medium length—spacer arm (total length added to target) is 27.0 angstroms, sufficient to minimize steric hindrance for binding

Aminooxy-biotin reagents such as this one are useful for biotinylating glycoproteins and other molecules that have oxidizable polysaccharides groups. The alkoxyamine group (also called an aminooxy or aminoxy group) conjugates to aldehydes of oxidized sugars. EZ-Link Alkoxyamine-PEG-Biotin reagents contain a multi-functional extended spacer arm that is a flexible, non-immunogenic hydrophilic polyethylene glycol (PEG), which imparts water solubility to labeled molecules. Consequently, antibodies labeled with pegylated biotin reagents exhibit less aggregation when stored in solution compared to antibodies labeled with reagents having only hydrocarbon spacers.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

Biotinylation reagents differ in reactivity, length, solubility, cell permeability and cleavability. Hydrazides and alkoxyamines are two types of carbonyl-reactive groups. Alkoxyamines (—O-NH2) react specifically with aldehyde groups in near-neutral conditions to form stable oxime linkages. The reaction is more efficient in the presence of aniline (Part No. 88944). Alternatively, alkoxyamines can be conjugated to carboxylic acids using EDC carbodiimide chemistry.

Reactive aldehyde groups can be generated in glycoproteins and other polysaccharide compounds by oxidation of constituent sugar diols using sodium periodiate (Part No. 20504). Sialic acid residues are common components of protein glycosylation and are easily converted to aldehydes with 1 mM NaIO4.

Qdot™ 705 ITK™ Carboxyl Quantum Dots (Invitrogen™)

Qdot® 705 ITK™ carboxyl quantum dots are the ideal starting material for preparing custom conjugates that require high loading of biomolecules. These materials are carboxylate functionalized and can be coupled to amine groups of proteins and modified oligonucleotides using EDC-mediated condensation. The coatings of these probes provides more binding sites than our Qdot® ITK™ amino quantum dots, but lacks PEG linkers that help to prevent non-specific interactions. These materials can be conjugated to X-PEG-amine bi-functional linkers for custom reactivity and higher specificity. Our Qdot® ITK™ carboxyl quantum dots are provided as 8 µM solutions and are available in all 9 Qdot® probe colors.

Important Features of Qdot® ITK™ Carboxyl Quantum Dots:
• Qdot® 705 ITK™ carboxyl quantum dot has emission maxima of ~705 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large Stokes shift
• Available in multiple colors
• Ideal labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the carboxyl-derivatized form, we offer Qdot® ITK™ quantum dots with amino and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

BODIPY™ FL Hydrazide (4,4-Difluoro-5,7-Dimethyl-4-Bora-3a,4a-Diaza-s-Indacene-3-Propionic Acid, Hydrazide) (Invitrogen™)

BODIPY® FL hydrazide can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a generate stable amine derivative by sodium borohydride (NaBH4) or sodium cyanoborohydride (NaCNH3). Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247).

EZ-Link™ Hydrazide-Biotin (Thermo Scientific™)

Thermo Scientific EZ-Link Hydrazide-Biotin is the shortest and simplest hydrazide-activated biotinylation reagent for labeling glycoproteins and other carbohydrate-containing compounds having oxidizable sugars or aldehydes.

Features of EZ-Link Hydrazide-Biotin:

Glycoprotein labeling—biotinylate glycosylated proteins at sialic acid residues for detection or purification using streptavidin probes or resins
Cell surface labeling—biotinylate and isolate cell surface glycoproteins
Aldehyde-reactive—reacts with aldehydes formed by periodate-oxidation of sugar groups
Hydrazide-activated—perform reactions at pH 4 to 6 in buffers such as sodium acetate
Irreversible—forms semi-permanent hydrazone bonds; spacer arm cannot be cleaved
Solubility—usually dissolved in DMSO before further dilution in aqueous buffers
Spacer arm length—15.7Å

This biotin hydrazide reagent enables simple and efficient biotin labeling of polyclonal antibodies and other glycoproteins. Mild oxidation of antibodies with sodium periodate produces reactive aldehydes on the carbohydrate moieties of the Fc portion that can be modified by hydrazides. This approach is advantageous for labeling antibodies because biotinylation occurs only at the sites of glycosylation, which are primarily in the Fc region of the antibody, far from the antigen binding site.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

Biotinylation reagents differ in reactivity, length, solubility, cell permeability and cleavability. Hydrazides and alkoxyamines are two types of carbonyl-reactive groups. Hydrazides (—NH-NH2) react specifically with aldehyde groups in slightly acidic conditions to form hydrazone linkages; these can be further reduced to stable secondary amine bonds using sodium cyanoborohydride (Part No. 44892). The reaction is more efficient in the presence of aniline (Part No. 88944). Alternatively, hydrazides can be conjugated to carboxylic acids using EDC carbodiimide chemistry.

Reactive aldehyde groups can be generated in glycoproteins and other polysaccharide compounds by oxidation of constituent sugar diols using sodium periodiate (Part No. 20504). Sialic acid residues are common components of protein glycosylation and are easily converted to aldehydes with 1 mM NaIO4.

Related Products
EZ-Link™ Biotin-LC-Hydrazide

Qdot™ 655 ITK™ Carboxyl Quantum Dots (Invitrogen™)

Qdot® 655 ITK™ carboxyl quantum dots are the ideal starting material for preparing custom conjugates that require high loading of biomolecules. These materials are carboxylate functionalized and can be coupled to amine groups of proteins and modified oligonucleotides using EDC-mediated condensation. The coatings of these probes provides more binding sites than our Qdot® ITK™ amino quantum dots, but lacks PEG linkers that help to prevent non-specific interactions. These materials can be conjugated to X-PEG-amine bi-functional linkers for custom reactivity and higher specificity. Our Qdot® ITK™ carboxyl quantum dots are provided as 8 µM solutions and are available in all 9 Qdot® probe colors.

Important Features of Qdot® ITK™ Carboxyl Quantum Dots:
• Qdot® 655 ITK™ carboxyl quantum dot has emission maxima of ~655 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large Stokes shift
• Available in multiple colors
• Ideal labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the carboxyl-derivatized form, we offer Qdot® ITK™ quantum dots with amino and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Texas Red™ Hydrazide, >90% single isomer (Invitrogen™)

The primary aliphatic amine of the red-fluorescent Texas Red® hydrazide can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a stable amine derivative by sodium borohydride (NaBH4) or sodium cyanoborohydride (NaCNH3) to form new biotinylated probes. Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247).

PDAM (1-Pyrenyldiazomethane) (Invitrogen™)

The fluorescent diazomethyl derivative PDAM (1-pyrenylyldiazomethane) has been commonly used to derivatize biomolecules. Diazoalkane react with the addition of catalysis and may be used for direct carboxylic acid modification of proteins and synthetic polymers. Fluorescent diazoalkanes also react with phosphates. PDAM is recommended as an alternative to ADAM because it has much better chemical stability. Moreover, the detection limit for PDAM for conjugates is reported to be about 20-30 femtomoles, which is five times better than reported for ADAM conjugates.