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SMCC (succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate) (Thermo Scientific™)

Thermo Scientific Pierce SMCC is an amine-to-sulfhydryl crosslinker that contains NHS-ester and maleimide reactive groups at opposite ends of a medium-length cyclohexane-stabilized spacer arm (8.3 angstroms).

Features of SMCC:

Reactive groups: NHS ester and maleimide
Reactive toward: amino and sulfhydryl groups
• Non-cleavable
• Water-insoluble (dissolve first in DMF or DMSO); compare to Sulfo-SMCC
• High purity, crystalline reagent can be used to create high-purity maleimide-activated derivatives
• Cyclohexane bridge confers added stability to the maleimide group making SMCC an ideal crosslinking agent for maleimide activation of proteins. Maleimide groups are stable for 64 hours in 0.1 M sodium phosphate buffer, pH 7 at 4°C.

Succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) is a non-cleavable and membrane permeable crosslinker. It contains an amine-reactive N -hydroxysuccinimide (NHS ester) and a sulfhydryl-reactive maleimide group. NHS esters react with primary amines at pH 7-9 to form stable amide bonds. Maleimides react with sulfhydryl groups at pH 6.5-7.5 to form stable thioether bonds. The maleimide groups of SMCC and Sulfo-SMCC and are unusually stable up to pH 7.5 because of the cyclohexane bridge in the spacer arm.

Applications:
• Enzyme labelling of antibodies - both enzyme and antibody specificity can be preserved
• Create specific bioconjugates via one- or two-step crosslinking reactions
• Create sulfhydryl-reactive, maleimide-activated carrier proteins for coupling haptens

Specifications:
We manufacture SMCC to the highest specifications to produce the most specific bioconjugates and maleimide-activated proteins, ensure the integrity of your data and to provide you with the highest degree of crosslinking consistency. Each lot of SMCC is tested to meet the following minimum specifications.

• Identity: IR scan shows only peaks characteristic of the structure and functional groups of SMCC cross linker
• Purity: ≥ 92% by NMR

Product References:
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
Sulfo-SMCC (sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate)

BS3 (bis(sulfosuccinimidyl)suberate) (Thermo Scientific™)

Thermo Scientific Pierce BS3 (Sulfo-DSS) is bis(sulfosuccinimidyl)suberate, an amine-to-amine crosslinker that is homobifunctional, water-soluble, non-cleavable and membrane impermeable.

BS3 contains an amine-reactive N-hydroxysulfosuccinimide (NHS) ester at each end of an 8-carbon spacer arm. NHS esters react with primary amines at pH 7-9 to form stable amide bonds, along with release of the N-hydroxysulfosuccinimide leaving group. Proteins, including antibodies, generally have several primary amines in the side chain of lysine (K) residues and the N-terminus of each polypeptide that are available as targets for NHS-ester crosslinking reagents.

Features of BS3:

Reactive groups: sulfo-NHS ester (both ends)
Reactive towards: amino groups (primary amines)
• Amine-reactive Sulfo-NHS ester reacts rapidly with any primary amine-containing molecule
• Water-soluble; compare with DSS
• Membrane-impermeable, allowing for cell surface labeling
• High-purity, crystalline reagent can be used to create high-purity crosslinked conjugates

Because it contains the hydrophilic sulfonyl moiety, BS3 crosslinker is soluble up to ~100 mM in water and many commonly used buffers, thus avoiding the use of organic solvents which may perturb protein structure. DSS, the non-water soluble analog of BS3 is also available for applications that require a less hydrophilic crosslinker (e.g., to effect intracellular crosslinking). DSS and BS3 have essentially identical crosslinking activity toward primary amines.

Properties of BS3:
• Alternative names: Sulfo-DSS
• Molecular formula: C16H18N2O14S2Na2
• Molecular weight: 572.43
• Spacer arm length: 11.4 Å (8 atoms)
• CAS number: 82436-77-9
• Reactive groups: NHS esters, react with primary amines at pH 7.0-9.0

Applications:
• Crosslink cell-surface proteins prior to cell lysis and immunoprecipitation
• Identify receptor-ligand interactions by chemical crosslinking
• "Fix" protein interactions to allow identification of weak or transient protein interactions
• Identify near-neighbor protein interactions
• Protein crosslinking to create bioconjugates via single-step reactions
• Immobilize proteins onto amine-coated surfaces

BS3 Specifications:
We manufacture BS3 to the highest specifications to produce the most specific bioconjugates, ensure the integrity of your data and to provide you with the highest degree of consistency. Each lot of BS3 is tested to meet the following minimum specifications:
• Purity: > 93% by quantitative NMR (the highest standard for crosslinker purity)
• Solubility: > 5.8 mg/mL in DI water, clear solution with no insoluble material

Product References
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
Pierce™ Premium Grade BS3
DSS (disuccinimidyl suberate)
BS(PEG)5 (PEGylated bis(sulfosuccinimidyl)suberate)
BS(PEG)9 (PEGylated bis(sulfosuccinimidyl)suberate)

Sulfo-SMCC (sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate) (Thermo Scientific™)

Thermo Scientific Pierce Sulfo-SMCC is a water-soluble, amine-to-sulfhydryl crosslinker that contains NHS-ester and maleimide reactive groups at opposite ends of a medium-length cyclohexane spacer arm (8.3 angstroms).

Features of Sulfo-SMCC:

Reactive groups: sulfo-NHS ester and maleimide
Reactive towards: amino and sulfhydryl groups
• Water-soluble (compare to SMCC), so crosslinking can be done in physiologic solutions
• High purity, crystalline reagent can be used to create high-purity maleimide-activated derivatives
• Cyclohexane bridge confers added stability to the maleimide group making Sulfo-SMCC the ideal crosslinking agent for maleimide activation of proteins. Maleimide groups are stable for 64 hours in 0.1 M sodium phosphate buffer, pH 7 at 4°C.

Sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC) is a non-cleavable and membrane impermeable crosslinker. It contains an amine-reactive N-hydroxysuccinimide (NHS ester) and a sulfhydryl-reactive maleimide group. NHS esters react with primary amines at pH 7-9 to form stable amide bonds. Maleimides react with sulfhydryl groups at pH 6.5-7.5 to form stable thioether bonds. The maleimide groups of Sulfo-SMCC and SMCC are unusually stable up to pH 7.5 because of the cyclohexane bridge in the spacer arm. Because it contains the hydrophilic sulfonyl moiety, Sulfo-SMCC is soluble up to ~10 mM in water and many commonly used buffers, thus avoiding the use of organic solvents which may perturb protein structure.

Applications:
• Enzyme labeling of antibodies - both enzyme and antibody specificity can be preserved
• Create specific bioconjugates via one- or two-step crosslinking reactions
• Create sulfhydryl-reactive, maleimide-activated carrier proteins for coupling haptens

Specifications:
Sulfo-SMCC is manufactured to the highest specifications to produce the most specific bioconjugates and maleimide-activated proteins, ensure the integrity of your data and to provide you with the highest degree of crosslinking consistency. Each lot of Sulfo-SMCC is tested to meet the following minimum specifications.

• Identity: IR scan shows only peaks characteristic of the structure and functional groups of Sulfo-SMCC crosslinker
• Purity: ≥ 90% by quantitative NMR (the highest standard for crosslinker purity)
• Solubility: ≥ 10 mg/mL in DI water

Product References:
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
Pierce™ Premium Grade Sulfo-SMCC (sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate)
SM(PEG)4 (PEGylated SMCC crosslinker)

LC-SMCC (succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxy-(6-amidocaproate)) (Thermo Scientific™)

Thermo Scientific Pierce LC-SMCC is an amine-to-sulfhydryl crosslinker that contains NHS-ester and maleimide reactive groups at opposite ends of a long cyclohexane-stabilized spacer arm (16.2 angstroms).

Features of LC-SMCC:

Reactive groups: NHS ester and maleimide
Reactive toward: amino and sulfhydryl groups
• Long-chain variety of SMCC
• High purity, crystalline reagent can be used to create high-purity maleimide-activated derivatives
• Non-cleavable
• Water-insoluble (dissolve first in DMF or DMSO)
• Cyclohexane bridge confers added stability to the maleimide group making LC-SMCC an ideal crosslinking agent for maleimide activation of proteins. Maleimide groups are stable for 64 hours in 0.1 M sodium phosphate buffer, pH 7 at 4°C.

LC-SMCC is a non-cleavable and membrane permeable crosslinker. It contains an amine-reactive N-hydroxysuccinimide (NHS ester) and a sulfhydryl-reactive maleimide group. NHS esters react with primary amines at pH 7-9 to form stable amide bonds. Maleimides react with sulfhydryl groups at pH 6.5-7.5 to form stable thioether bonds. The maleimide groups of LC-SMCC and are unusually stable up to pH 7.5 because of the cyclohexane bridge in the spacer arm.

Applications:
• Ideal reagent for enzyme labeling of antibodies, both enzyme activity and antibody specificity can be preserved
• Create specific bioconjugates via one- or two-step crosslinking reactions
• Create sulfhydryl-reactive, maleimide-activated carrier proteins for coupling haptens

LC-SMCC is often used for the preparation of antibody-enzyme and hapten-carrier conjugates. In this type of conjugation, the NHS ester is reacted first with the antibody, excess crosslinking reagent removed and then the sulfhydryl-containing enzyme molecule is added. This two-step reaction scheme results in formation of specific antibody-enzyme conjugates.

LC-SMCC is a reagent of choice for creating stable maleimide-activated carrier proteins that will spontaneously react with sulfhydryls. In this application, the NHS ester of LC-SMCC is reacted with lysine residues on the carrier protein, converting them to reactive maleimides. These relatively stable maleimide-activated intermediates may be lyophilized and stored for later conjugation to a hapten.

Specifications:
We manufacture LC-SMCC to the highest specifications to produce the most specific bioconjugates and maleimide-activated proteins, ensure the integrity of your data and to provide you with the highest degree of crosslinking consistency. Each lot of LC-SMCC is tested to meet the following minimum specifications.

• Identity: IR scan shows only peaks characteristic of the structure and functional groups of LC-SMCC crosslinker
• Purity: ≥ 90% by NMR

Product References:

Crosslinker Application Guide -- search for recent literature references for this product

Related Products
SMCC (succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate)
Sulfo-SMCC (sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate)

Pierce™ Sulfo-SANPAH, No-Weigh™ Format (Thermo Scientific™)

Thermo Scientific Pierce Sulfo-SANPAH is a hetero-bifunctional crosslinker that contains an amine-reactive N-hydroxysuccinimide (NHS) ester and a photoactivatable nitrophenyl azide. NHS esters react efficiently with primary amino groups (-NH2) in pH 7–9 buffers to form stable amide bonds. The reaction results in the release of sulfo-N-hydroxy-succinimide. When exposed to UV light, nitrophenyl azides form a nitrene group that can initiate addition reactions with double bonds, insertion into C-H and N-H sites, or subsequent ring expansion to react with a nucleophile (e.g., primary amines). Sulfo-SANPAH, supplied as a sodium salt, is useful for cell-surface protein crosslinking and possesses charged groups for water solubility to a concentration of 10 mM.

Thermo Scientific No-Weigh products are specialty reagents provided in a pre-aliquoted format. The pre-weighed packaging prevents the loss of reagent reactivity and contamination over time by eliminating the repetitive opening and closing of the vial. The format enables use of a fresh vial of reagent each time, eliminating the hassle of weighing small amounts of reagents and reducing concerns over reagent stability.

Features of Sulfo-SANPAH:

Reactive groups: sulfo-NHS ester and nitrophenyl azide
Reactive towards: amino groups and any nucleophile
• Non-cleavable
N-Sulfosuccinimidyl-6-(4'-azido-2'-nitrophenylamino) hexanoate
• Optimal photolysis occurs at 320-350 nm; minimizes damage to biomolecules by irradiation
• Water soluble; non-cleavable

Product References:
Crosslinker Application Guide -- search for recent literature references for this product

BS(PEG)5 (PEGylated bis(sulfosuccinimidyl)suberate) (Thermo Scientific™)

BS(PEG)5 is a bis-succinimide ester-activated PEG compound used for crosslinking between primary amines (—NH2) in proteins and other molecules. The N-hydroxysuccinimide ester (NHS) groups at either end of the PEG5 spacer react specifically and efficiently with lysine and N-terminal amino groups at pH 7-9 to form stable amide bonds.

Features of BS(PEG)5:

Reactive groups: sulfo-NHS ester (both ends)
Reactive towards: amino groups (primary amines)
• NHS esters react with—NH2 groups at pH 7-9, forming stable amide bonds
• Water-soluble; compare to non-pegylated BS3 (also soluble) and DSS (water-insoluble)
• Membrane-impermeable, allowing for cell surface labeling
• Irreversibly crosslink proteins or peptides by flexible PEG spacer arms
• Polyethylene glycol spacer arms help maintain conjugate solubility
• Pure compound with defined structure and molecular weight, ensuring reproducible protein-modification effects
• PEG spacer provides unique advantages, including increased stability, reduced tendency toward aggregation and reduced immunogenicity
• Ideal for small molecule or peptide conjugations

Alternative Names for BS(PEG)n:

• Bis-NHS-dPEG
• NHS-PEG-NHS
• BS(PEO)5
• Bis(NHS)PEO5
• BS-PEO9
• dPEG NHS ester
• Bis-succinimide ester PEG 400

Product References
Crosslinker Application Guide -- search for recent literature references for this product
Bioconjugate Techniques, Academic Press (Part No. 20036)

Related Products
BS(PEG)9 (PEGylated bis(sulfosuccinimidyl)suberate)
BS3 (bis(sulfosuccinimidyl)suberate)

BMOE (bismaleimidoethane) (Thermo Scientific™)

Thermo Scientific Pierce BMOE is a short-arm, maleimide crosslinker for covalent, irreversible conjugation between sulfhydryl groups (e.g., protein or peptide cysteines).

Features of BMOE:

Reactive groups: maleimide (both ends)
Reactive towards: sulfhydryl groups
• Short (8.0Å), sulfhydryl-to-sulfhydryl crosslinker, composed of maleimide groups and 7-atom spacer arm
• Shortest bismaleimide crosslinker available for close proximity crosslinking
• Water-insoluble—dissolve first in DMF or DMSO, then add to aqueous reaction buffers
• Noncleavable

Related Products
BMB (1,4-bismaleimidobutane)
BMH (bismaleimidohexane)
BM(PEG)2 (1,8-bismaleimido-diethyleneglycol)
BM(PEG)3 (1,11-bismaleimido-triethyleneglycol)

NHS-Phosphine (Thermo Scientific™)

Thermo Scientific NHS-Phosphine is an amine-reactive compound that can be used to derivatize primary amines of proteins or amine-coated polymer surfaces for ligation to azide-tagged molecules.

Features of NHS-Phosphine:

Soluble—reagent easily dissolves in water-miscible solvents for subsequent dilution in aqueous reaction mixtures with cell lysates and other biological samples
Compatible—reaction chemistry occurs effectively in simple buffer conditions; requires no accessory reagents such as copper or reducing agents
Specific—NHS esters are specific for covalent attachment to primary amines (side chain of lysine or N-terminus of polypeptides)
Chemoselective—azide and phosphine groups do not react or interfere with components of biological samples (bioorthogonal) but conjugate to one another with high efficiency

This NHS-ester compound reacts to form covalent bonds with primary amines (e.g., side chain of lysine residues or aminosilane-coated surfaces). The phosphine group (PPh2) reacts with azide-labeled molecules by a mechanism known as Staudinger chemistry, enabling efficient and specific conjugation of derivatized molecules in biological samples. In combination with different azide-tagged compounds, this NHS-Phosphine reagent facilitates a variety of labeling and crosslinking experimental strategies for investigating protein interactions and cellular pathways.

Related Products
NHS-Phosphine
NHS-Azide

SMPT (4-succinimidyloxycarbonyl-alpha-methyl-α(2-pyridyldithio)toluene) (Thermo Scientific™)

Thermo Scientific Pierce SMPT is a long-chain crosslinker for amine-to-sulfhydryl conjugation via NHS-ester and pyridyldithiol reactive groups that form strong (hindered) yet cleavable (reducible) disulfide bonds with cysteine sulfhydryls.

Features of SMPT:

Reactive groups: NHS ester and pyridyldithiol
Reactive towards: amino and sulfhydryl groups
• Cleavable with disulfide reducing agents
• Water-insoluble (dissolve first in DMF or DMSO)
• Contains a hindered disulfide bond; has formed immunotoxins with improved stability
• In vitro, an SMPT conjugate was as effective as conjugates formed with SPDP and 2-IT
• Compare to other varieties of SPDP-type reagents, including pegylated forms

Product References:
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
SPDP (succinimidyl 3-(2-pyridyldithio)propionate)

Pierce™ Premium Grade DSP (dithiobis(succinimidyl propionate)) (Thermo Scientific™)

Thermo Scientific Pierce Premium Grade DSP is our highest quality formulation of this popular amine-reactive, cleavable crosslinker, specially characterized for applications where product integrity and risk minimization are paramount.

Compared to the standard grade product, Premium Grade DSP provides more clearly defined quality and product support by including (a) increased analytical testing and product characterization, (b) greater batch-specific information and quality assurance review, (c) extensive lot sample retention, and (d) change control notification. DSP is dithiobis(succinimidyl propionate), an amine-reactive crosslinker having NHS-ester reactive ends and a cleavable disulfide bond in its spacer arm. DSP contains an amine-reactive N-hydroxysuccinimide (NHS) ester at each end of an 8-carbon spacer arm. NHS esters react with primary amines at pH 7-9 to form stable amide bonds, along with release of the N-hydroxy-succinimide leaving group. Proteins, including antibodies, generally have several primary amines in the side chain of lysine (K) residues and the N-terminus of each polypeptide that are available as targets for NHS-ester crosslinking reagents.

Features of Premium Grade DSP:

DSP—a thiol-cleavable, homobifunctional and amine-reactive crosslinking agent
High quality—identity and purity confirmed by several tests, including quantitative NMR
Product integrity—enhanced level of testing and characterization compared to standard grade
Lot retention—ample supply of past lots retained to ensure future process testing
Change management—Change Control Notification (CCN) service
Consistent manufacture—batch-specific manufacturing documentation review

Applications:
• Chemical crosslinking of intracellular proteins prior to cell lysis and immunoprecipitation
• "Fix" protein interactions to allow identification of weak or transient protein interactions
• Fix tissues for immunostaining without damaging RNA
• Protein crosslinking to create bioconjugates via single-step reactions
• Immobilize proteins onto amine-coated surfaces

Product References
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
DSP (dithiobis(succinimidyl propionate)), Lomant's Reagent

DST (disuccinimidyl tartrate) (Thermo Scientific™)

Thermo Scientific Pierce DST, also called disuccinimidyl tartrate, is a water-soluble crosslinker that contains amine-reactive NHS ester ends around a 4-atom spacer arm, whose central diol can be cleaved by periodate oxidation.

Features of disuccinimidyl tartrate:

Reactive groups: NHS ester (both ends)
Reactive towards: amino groups (primary amines)
• Soluble in DMSO or DMF at a concentration of ~10 mM (3 mg/mL)
• Cleavable by sodium meta-periodate (Part No. 20504)
• Ideal for applications in which crosslink cleavability is desired without disturbing protein disulfide bonds

Product References:

Crosslinker Application Guide -- search for recent literature references for this product

Related Products
DST (disuccinimidyl tartrate)

EMCH (N-ε-maleimidocaproic acid hydrazide) (Thermo Scientific™)

Thermo Scientific Pierce EMCH is a mid-length, maleimide-and-hydrazide crosslinker for conjugating sulfhydryls (cysteines) to carbonyls (aldehyde or ketones, such as those formed by oxidation of glycoprotein carbohydrates).

Features of EMCH:

Reactive groups: maleimide and hydrazide
Reactive towards: sulfhydryl groups and carbonyl (aldehyde) groups
• Mid-length (11.8Å), sulfhydryl-to-aldehyde crosslinker with simple spacer arm (noncleavable)
• Maleimide group reacts with sulfhydryl groups to form stable thioether linkages
• Hydrazide group conjugates to oxidized sugars of glycoproteins and carbohydrates
• Use sodium meta-periodate to oxidize glycosylation (e.g., sialic acid) to reactive aldehyde groups
• Use with EDC to conjugate primary amine of hydrazide group to carboxyl groups

3,3'-N-[ε-Maleimidocaproic acid] hydrazide, trifluoroacetic acid salt (EMCH) is a water-soluble, heterobifunctional, membrane permeable crosslinker. It contains a sulfhydryl reactive maleimide group and carbonyl reactive hydrazide group at each end of a 6-carbon spacer arm. Maleimides react with sulfhydryls at pH 6.5-7.5 to form stable thiol ether bonds, along with release of the maleimide leaving group. Proteins with cysteine residues not involved in disulfide bond formation are targets for maleimide reactive groups. Carbonyl groups, whilst not found naturally on proteins can be formed by ring sugar reduction to form aldehydes which react with hydrazides at pH5.5-7.5.

Applications:
• Chemical crosslinking of glycoproteins to sulfhydryl-containing molecules
• Use with EDC for reactivity toward carboxyl groups

Specifications of EMCH:
We manufacture EMCH to the highest specifications to produce the most specific bioconjugates, ensure the integrity of your data and to provide you with the highest degree of consistency. Each lot of EMCH is tested to meet the following minimum specifications:

• NMR purity: >90%
• Melting point: 99-110°C
• Identity: IR scan shows only peaks characteristic of the structure and functional groups of EMCH

Product References:
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
BMPH
MPBH
KMUH

BS3-d0 (bis(sulfosuccinimidyl) suberate-d0) (Thermo Scientific™)

Thermo Scientific Pierce BS3-d0/d4 reagents form a matched set of heavy (deuterated) and light mass varieties of BS3 amine-reactive crosslinker that facilitates the identification of crosslinked peptides by mass spectrometry.

The BS3-d0/d4 reagents are mass-analogs of the popular BS3 crosslinker (Part No. 21580). The d-zero variety (BS3-d0) possesses ordinary hydrogen atoms while the d-four variety (BS3-d4) contains four deuterium atoms that make it exactly four hydrogen mass units heavier. When the two varieties are mixed and used to crosslink interacting proteins, distinctive mass patterns result that enable unambiguous identification of the crosslinked molecules.

Features of BS3-d0/d4 reagents:

Deuterium-labeled BS3 and its standard hydrogen-only analog—specially manufactured for crosslinking protein structure:function analysis by mass spectrometry
Easy identification of crosslinked fragments—peptide masses differing by 4 units unambiguously identify crosslink at specific loci within a protein interaction structure
Application-specific instructions—help guide the first time user through the application
Method requires only microgram amounts of protein—excellent alternative to NMR or X-ray crystallography-based methods that require large amounts of protein, special solvents or crystal formation

Addition of an equimolar mixture of two identical crosslinking agents that differ only in the number of deuterium atoms in their chemical structures provides a powerful method to identify low-abundance, singly-crosslinked peptides by mass spectrometry. Crosslinking protein interactions with BS2G-d0/d4 reagents generates distinctive mass patterns in which crosslinked peptides differ by 4 mass units after enzymatic digestion of the crosslinked protein or protein complex. Further analysis of the reaction products can yield low resolution three dimensional structure information.

BS3-d0/d4 and BS2G-d0/BS2G-d4 reagents are homobifunctional, amine-reactive, non-cleavable, water-soluble crosslinking agents with defined spacer arm lengths. These reagents can act as molecular rulers for estimation of spatial relationships in protein structure-function studies. Both light and deuterated analogs react efficiently with primary amine (—NH2) at pH 7-9 to form stable amide bonds. Proteins generally contain several primary amines in the side chain of Lysine (K) residues and the N-terminus of each polypeptide that are available as targets for the two sulfo-NHS ester reactive groups found in each of these reagents. These reagents are supplied as a sodium salt and are soluble in water at a concentration up to 10 mM.

Related Products
BS3-d4 (bis(sulfosuccinimidyl) 2,2,7,7-suberate-d4)

Sulfo-SBED Biotin Label Transfer Reagent, No-Weigh™ Format (Thermo Scientific™)

The Thermo Scientific Pierce Sulfo-SBED Biotin Label Transfer Reagent is a multifunctional reagent for labeling a purified protein and then covalently transferring the attached biotin tag onto specific interactors of that protein.

Sulfo-SBED is the abbreviation for Sulfo-N-hydroxysuccinimidyl-2-(6-[biotinamido]-2-(p-azido benzamido)-hexanoamido) ethyl-1,3'-dithioproprionate. It is a heterobifunctional chemical crosslinker capable of covalently attaching to primary amines at one end and to nearly any protein functional group at the other end. Unlike typical crosslinkers, Sulfo-SBED also includes a biotin group and a cleavable disulfide spacer arm. Together these features allow one to sequentially crosslink interacting proteins and transfer the biotin affinity tag from one protein (i.e., a purified "bait" protein) to another (possibly unknown "prey" protein). Label Transfer is a powerful in vitro method for protein interaction discovery. A growing number of publications feature the use of Sulfo-SBED Biotin Label Transfer Reagent to identify previously unknown protein interaction binding partners and to more fully characterize the specific protein binding domains of other protein interactions.

Typical protocol for label transfer experiment:

• Add a few microliters of dissolved Sulfo-SBED Reagent to 0.5-1 mL of purified bait protein in PBS.
• Incubate mixture for 30-120 minutes on ice or at room temperature in the dark.
• Desalt or dialyze (in subdued light) to remove excess non-reacted Sulfo-SBED from the labeled bait protein.
• Add labeled bait protein to cell lysate or other solution containing putative target protein interactors ("prey").
• When interaction complexes have formed, expose the solution to ultraviolet light (365 nm) for several minutes.
• Analyze products by one of several methods:
Western Blotting: Cleave crosslinks in DTT, separate proteins by SDS-PAGE, and detect biotinylated bands by Western blotting with streptavidin-HRP.
Purification and Mass Spec or Sequencing: Affinity-purify biotinylated proteins or peptide fragments following trypsin digestion and perform MS or sequencing to characterize the proteins involved.

Related Products
Sulfo-SBED Biotin Label Transfer Kit - Western Blot Application

EMCS (N-ε-malemidocaproyl-oxysuccinimide ester) (Thermo Scientific™)

Thermo Scientific Pierce EMCS is an amine-to-sulfhydryl crosslinker that contains NHS-ester and maleimide reactive groups at opposite ends of a medium-length spacer arm (9.4 angstroms).

Features of EMCS:

Reactive groups: NHS ester and maleimide
Reactive towards: amino and sulfhydryl groups
• C6-homolog of aliphatic spacer series which includes AMAS, BMPS, GMBS and EMCS
• NHS ester end couples with primary amines at pH 7-9 to form stable amide bonds
• Maleimides react with -SH groups at pH 6.5-7.5, forming stable thioether linkages
• Non-cleavable
• Water-insoluble (dissolve first in DMF or DMSO); compare to Sulfo-EMCS
• Increased sphere of coupling vs. GMBS
• Short aliphatic spacer has low potential for eliciting an immune response

Product References:
Crosslinker Application Guide -- search for recent literature references for this product