Shop All Protein Analysis Reagents

Cross Reactivity


Immunoassay Kit Format


No. of Samples


Target Organism Class


Target Specificity


CaptureSelect™ KappaXL EvolveD™ Column Thermo Scientific™

CaptureSelect KappaXL EvolveD columns are ready-to-use columns designed specifically for use in biopharmaceutical applications. These pre-packed columns are suitable for cGMP manufacturing and have the following features:
• Prepared and packed in a classified ISO7 environment
• An entirely non-metallic flow path
• Qualified in terms of performance and pressure flow characteristics
• Suitable for direct connection to standard chromatography systems
• Available Regulatory Support File
• Packed with CaptureSelect KappaXL Affinity Matrix, offering high dynamic binding capacity and high resolution over a wide range of flow rates

Please note that CaptureSelect EvolveD affinity columns are made to order. They are custom manufactured two-at-a-time, so are offered only in quantities that are a multiple of two. For detailed information on the resin, please see the CaptureSelect EvolveD column manual below.

Operating and technical specifications
Column type10-cm bed height20-cm bed height
Column diameter (cm)7102071020
Column length (cm)101010202020
Cross-sectional area (cm2)38.578.5314.238.578.5314.2
Column volume (mL)385785314277015706284

• Pressure rating (bar/psi): 4/58
• Operating temperature: 2–30°C, dependent on the resin packed
• Bed support size: 8 µm
• Inlet/outlet internal diameter: 3 mm or 6 mm depending on the column diameter
• Inlet/outlet port connections: 25-mm TC sanitary fitting

View our comprehensive column overview › (Select the Antibody Purification tab.)

CaptureSelect KappaXL Affinity Matrix is designed for the purification of recombinant human Ig’s (including IgA, IgM, IgD, and IgE) containing a Kappa light chain and their Fab fragments.

Features of this affinity matrix include:
• Purification of Kappa monoclonal antibodies, Fab-, and Fab2 fragments directly from complex source materials in a single step with high purity and yield
• Mild elution for Fab fragments and antibodies
• Human specific, no binding to bovine antibodies
• Non-animal derived

View other antibody affinity matrices ›

Free of animal components
CaptureSelect products are affinity ligands created with proprietary technology based on camelid-derived single-domain antibody fragments. The KappaXL ligand is a 13-kDa fragment comprising the three complementarity determining regions (CDRs) that form the antigen binding domain. The ligand is efficiently produced by the yeast Saccharomyces cerevisiae in a production process free of animal components.

Main characteristics:

Matrix: agarose-based, epoxide-activated
Average particle size: 65 ± 10 µm
Ligand: CaptureSelect KappaXL affinity ligand
Ligand coupling method: aldehyde coupling via NH2 residues of the ligand
Binding capacity: 29–38 g IgG/L resin depending on flow rate, column height, and contact time
Elution conditions: 20 mM citric acid, pH 3.5
Max. operation pressure: 2 bar
Formulation buffer: 20% (v/v) ethanol

CaptureSelect™ KappaXP EvolveD™ Column Thermo Scientific™

CaptureSelect KappaXP EvolveD columns are ready-to-use columns designed specifically for use in biopharmaceutical applications. These pre-packed columns are suitable for cGMP manufacturing and have the following features:
• Prepared and packed in a classified ISO7 environment
• An entirely non-metallic flow path
• Qualified in terms of performance and pressure flow characteristics
• Suitable for direct connection to standard chromatography systems
• Available Regulatory Support File
• Packed with CaptureSelect KappaXP Affinity Matrix, offering high dynamic binding capacity and high resolution over a wide range of flow rates

Please note that CaptureSelect EvolveD affinity columns are made to order. They are custom manufactured two-at-a-time, so are offered only in quantities that are a multiple of two. For detailed information on the resin, please see the CaptureSelect EvolveD column manual below.

Operating and technical specifications
Column type10-cm bed height20-cm bed height
Column diameter (cm)7102071020
Column length (cm)101010202020
Cross-sectional area (cm2)38.578.5314.238.578.5314.2
Column volume (mL)385785314277015706284

• Pressure rating (bar/psi): 4/58
• Operating temperature: 2–30°C, dependent on the resin packed
• Bed support size: 8 µm
• Inlet/outlet internal diameter: 3 mm or 6 mm depending on the column diameter
• Inlet/outlet port connections: 25-mm TC sanitary fitting

View our comprehensive column overview › (Select the Antibody Purification tab.)

CaptureSelect KappaXP Affinity Matrix recognizes the kappa light-chain of human antibodies, enabling purification of all Kappa containing Ig’s, Fab, and Fab2 fragments directly from complex sources and feed streams.

Features of this affinity matrix include:
• Purification of Kappa monoclonal antibodies, Fab-, and Fab2 fragments directly from complex source materials in a single step with high purity and yield
• Mild elution for Fab fragments and antibodies
• Human specific, no binding to bovine antibodies
• Excellent pH stability up to 100 mM NaOH for limited exposure
• Non-animal derived

View other antibody affinity matrices ›

Free of animal components
CaptureSelect products are affinity ligands created with proprietary technology based on camelid-derived single-domain antibody fragments. The KappaXP ligand is a 13-kDa fragment comprising the three complementarity determining regions (CDRs) that form the antigen binding domain. The ligand is efficiently produced by the yeast Saccharomyces cerevisiae in a production process free of animal components.

Main characteristics:

Matrix: agarose-based, epoxide-activated
Average particle size: 65 ± 10 µm
Ligand: CaptureSelect KappaXP affinity ligand
Ligand coupling method: aldehyde coupling via NH2 residues of the ligand
Binding capacity: 20–30 g IgG Kappa-Fab/liter resin depending on flow rate, column height, and contact time
Elution conditions: 20 mM citric or acetic acid, pH 3–4; 100 mM Tris, 1.5 M MgCl2 pH 6
Max. operation pressure: 2 bar
Formulation buffer: 20% (v/v) ethanol

Zenon™ Human IgG Labeling Kit Invitrogen™

Take advantage of a fast, versatile, and reliable method for producing antibody (IgG) conjugates for immunocytochemistry (ICC), immunohistochemistry (IHC), flow cytometry, and cell imaging with the Invitrogen Zenon™ Human IgG Labeling Kits. Simplify your laboratory applications and reduce antibody cross-reactivity while also achieving efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions.

CaptureSelect™ tPA EvolveD™ Column Thermo Scientific™

CaptureSelect tPA EvolveD columns are ready-to-use columns designed specifically for use in biopharmaceutical applications. These pre-packed columns are suitable for cGMP manufacturing and have the following features:
• Prepared and packed in a classified ISO7 environment
• An entirely non-metallic flow path
• Qualified in terms of performance and pressure flow characteristics
• Suitable for direct connection to standard chromatography systems
• Available Regulatory Support File
• Packed with CaptureSelect tPA Affinity Matrix, offering high dynamic binding capacity and high resolution over a wide range of flow rates

Please note that CaptureSelect EvolveD affinity columns are made to order. They are custom manufactured two-at-a-time, so are offered only in quantities that are a multiple of two. For detailed information on the resin, please see the CaptureSelect EvolveD column manual below.

Operating and technical specifications
Column type10-cm bed height20-cm bed height
Column diameter (cm)7102071020
Column length (cm)101010202020
Cross-sectional area (cm2)38.578.5314.238.578.5314.2
Column volume (mL)385785314277015706284

• Pressure rating (bar/psi): 4/58
• Operating temperature: 2–30°C, dependent on the resin packed
• Bed support size: 8 µm
• Inlet/outlet internal diameter: 3 mm or 6 mm depending on the column diameter
• Inlet/outlet port connections: 25-mm TC sanitary fitting

View our comprehensive column overview › (Select the Antibody Purification tab.)

CaptureSelect tPA Affinity Matrix is designed for the purification of human tissue plasminogen activator from recombinant sources.

Features of this affinity matrix include:
• Selective for human tPA
• Enables efficient purification of recombinant tPA with high yields and purity
• Excellent pH stability up to 50 mM NaOH for limited exposure
• Non-animal derived

View other biosimilars and recombinant proteins affinity matrices ›

Free of animal components
CaptureSelect products are affinity ligands created with proprietary technology based on camelid-derived single-domain antibody fragments. The tPA ligand is a 13-kDa fragment comprising the three complementarity determining regions (CDRs) that form the antigen binding domain. The ligand is efficiently produced by the yeast Saccharomyces cerevisiae in a production process free of animal components.

Main characteristics:

Matrix: agarose-based, epoxide-activated
Average particle size: 65 ± 10 µm
Ligand: CaptureSelect tPA affinity ligand
Ligand coupling method: aldehyde coupling via NH2 residues of the ligand
Binding capacity: 8–10 mg tPA/mL resin depending on flow rate, column height, and contact time
Neutral elution conditions: 20 mM Tris, 2.0 M MgCl2, 0.2 M arginine, pH 7.0
Acidic elution conditions: 0.1 M glycine, pH 3.0
Max. operation pressure: 2 bar
Formulation buffer: 20% (v/v) ethanol

DAPI (4',6-diamidino-2-phenylindole, dihydrochloride) Thermo Scientific™

Thermo Scientific Pierce DAPI Nuclear Counterstains are high-purity forms of diamidino-2-phenylindole dye for fixed-cell, fluorescent staining of DNA content and nuclei for cellular imaging techniques.

DAPI (diamidino-2-phenylindole) is a blue fluorescent probe that fluoresces brightly upon selectively binding to the minor groove of double stranded DNA, where its fluorescence is approximately 20-fold greater than in the nonbound state. Its selectivity for DNA and high cell permeability allows efficient staining of nuclei with little background from the cytoplasm. DAPI is a classic nuclear counterstain for immunofluorescence microscopy, as well as an important component of high-content screening methods requiring cell-based quantitation of DNA content.

Features of DAPI Nuclear Counterstain:

DAPI dye—diamidino-2-phenylindole is a blue fluorescent stain specific for DNA
Convenient—choose powder or easy-to-use DAPI dye solution (1 mg/mL)
Cellular imaging—cell-permeable dye is effective for fixed-cell staining and quantitation of DNA content
Counterstain—ideal for use alongside detection of specific targets with fluorescent antibodies for fluorescence microscopy or high-content screening (HCS)

Properties of DAPI Fluorescent Dye:

Alternative names: DAPI Stain, DAPI Dye, DNA Content Counterstain
Chemical name(s): 4,6'-diamidino-2-phenylindole, dihydrochloride; 4',6-diamidine-2-phenyl indole; 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride
Molecular formula: C16H15N5·2HCl
Molecular weight: 350.25
Excitation wavelength: 341±3 nm (near 360 nm when bound to dsDNA)
Emission wavelength: 452±3 nm (456 to 460 nm when bound to dsDNA)
Extinction coefficient: >30,600/M cm at 347 nm in methanol
CAS #: 28718-90-3
Purity: > 95% (most lots >98%) by HPLC at 240 nm
Solubility: >1 mg/mL in water; compound is soluble in DMF, water and various non-phosphate aqueous buffers
Reactive groups: None; binds to minor groove of double-stranded DNA

As a counterstain in fluorescence imaging methods, DAPI is compatible with antibodies and other probes labeled with fluorescein and rhodamine dyes, as well as with Thermo Scientific DyLight Fluors. DAPI has greater photostability than Hoechst dyes, although Hoechst 33342 can be use for live cell imaging while use of DAPI is confined to fixed cells. DAPI is offered in powdered solid and aqueous solution forms.

Applications for DAPI Stain:

• Assaying DNA in solution (ref.4)
• Diagnosing mycoplasmal infection of cell cultures (ref.5)
• Measuring nuclear content and sorting chromosomes in flow cytometry (ref.6)
• Assessing apoptosis (ref.7)
• Detecting nuclei and organellar DNA in immunofluorescent and in situ hybridization procedures (ref.2,8)
• Replacing ethidium bromide for staining DNA in agarose gels (ref.5,9)
• Counterstaining nuclei in histochemical methods when red-fluorescent antibodies have been used to detect specific targets (ref.8)
• Reports also indicate that DAPI will bind to polyphosphates and other polyanions (ref.10), dextran sulfate (ref.11) and SDS (ref.12).

Related Products
DAPI Solution (1 mg/mL)

Tetramethylrhodamine Cadaverine, 5-(and-6)-((N-(5-Aminopentyl) Amino) Carbonyl) Tetramethylrhodamine, mixed isomers Invitrogen™

The primary aliphatic amine of tetramethylrhodamine cadaverine 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). This material consists of the 5- and 6- isomer. Please see the structure for additional details.

Streptavidin, R-Phycoerythrin Conjugate (SAPE) - 1 mg/mL Invitrogen™

Streptavidin is a bacterially derived biotin-binding protein that exhibits less nonspecific binding than avidin. Phycoerythrin also known as R-Phycoerythrin (RPE) is an intensely bright phycobiliprotein isolated from red algae with absorption maxima at approximately 496, 546 and 565 nm, and a fluorescence emission maximum of ~578 nm. Used in flow, microplate assays and microarrays, this has remained one of our top three selling products for decades—a proven performer that you can trust.

Important Features of Streptavidin RPE
• Biotin Detection with high quantum efficiency photoprotein
• 5–10 times brighter than organic fluors
• High water solubility
• Ideal for Flow, microarrays and microplate assays
• Also available as Premium grade with higher purity confirmed by HPLC (S21388)

Streptavidin and RPE
The high affinity of avidin, an egg-white protein, for biotin was first exploited in histochemical applications in the mid-1970s. Avidin, and its bacterial counterpart, streptavidin (from Streptomy cesavidinii), have since become standard reagents for diverse detection schemes. Streptavidin, a nonglycosylated 52,800-dalton protein, exhibits less nonspecific binding than avidin.

Rhodophyta Phycoerythrin (RPE) has a MW of 240,000 Daltons and has a quantum efficiency of 78% making it an incredibly bright reagent. However, the photostability is extremely poor and is not traditionally recommended for microscopy. But the broad absorption and bright orange signal may it ideal for flow, microplate and microarray applications whenever sensitive detection of biotins is required.

Learn more about avidin biotin detection in general

Learn more about SAV-RPE

DAPI Solution (1 mg/mL) Thermo Scientific™

Thermo Scientific Pierce DAPI Nuclear Counterstains are high-purity forms of diamidino-2-phenylindole dye for fixed-cell, fluorescent staining of DNA content and nuclei for cellular imaging techniques.

Also available as a room-temperature-stable, ready-to-use solution: NucBlue Fixed Cell Ready Probes Reagent.
See other Ready Probes ready-to-use imaging reagents and accessories ›

DAPI (diamidino-2-phenylindole) is a blue fluorescent probe that fluoresces brightly upon selectively binding to the minor groove of double stranded DNA, where its fluorescence is approximately 20-fold greater than in the nonbound state. Its selectivity for DNA and high cell permeability allows efficient staining of nuclei with little background from the cytoplasm. DAPI is a classic nuclear counterstain for immunofluorescence microscopy, as well as an important component of high-content screening methods requiring cell-based quantitation of DNA content.

Features of DAPI Nuclear Counterstain:

DAPI dye—diamidino-2-phenylindole is a blue fluorescent stain specific for DNA
Convenient—choose powder or easy-to-use DAPI dye solution (1 mg/mL)
Cellular imaging—cell-permeable dye is effective for fixed-cell staining and quantitation of DNA content
Counterstain—ideal for use alongside detection of specific targets with fluorescent antibodies for fluorescence microscopy or high-content screening (HCS)

Properties of DAPI Fluorescent Dye:

Alternative names: DAPI Stain, DAPI Dye, DNA Content Counterstain
Chemical name(s): 4,6'-diamidino-2-phenylindole, dihydrochloride; 4',6-diamidine-2-phenyl indole; 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride
Molecular formula: C16H15N5·2HCl
Molecular weight: 350.25
Excitation wavelength: 341±3 nm (near 360 nm when bound to dsDNA)
Emission wavelength: 452±3 nm (456 to 460 nm when bound to dsDNA)
Extinction coefficient: >30,600/M cm at 347 nm in methanol
CAS #: 28718-90-3
Purity: > 95% (most lots >98%) by HPLC at 240 nm
Solubility: >1 mg/mL in water; compound is soluble in DMF, water and various non-phosphate aqueous buffers
Reactive groups: None; binds to minor groove of double-stranded DNA

As a counterstain in fluorescence imaging methods, DAPI is compatible with antibodies and other probes labeled with fluorescein and rhodamine dyes, as well as with Thermo Scientific DyLight Fluors. DAPI has greater photostability than Hoechst dyes, although Hoechst 33342 can be use for live cell imaging while use of DAPI is confined to fixed cells. DAPI is offered in powdered solid and aqueous solution forms.

Applications for DAPI Stain:

• Assaying DNA in solution (ref.4)
• Diagnosing mycoplasmal infection of cell cultures (ref.5)
• Measuring nuclear content and sorting chromosomes in flow cytometry (ref.6)
• Assessing apoptosis (ref.7)
• Detecting nuclei and organellar DNA in immunofluorescent and in situ hybridization procedures (ref.2,8)
• Replacing ethidium bromide for staining DNA in agarose gels (ref.5,9)
• Counterstaining nuclei in histochemical methods when red-fluorescent antibodies have been used to detect specific targets (ref.8)
• Reports also indicate that DAPI will bind to polyphosphates and other polyanions (ref.10), dextran sulfate (ref.11) and SDS (ref.12).

Related Products
DAPI (4',6-diamidino-2-phenylindole, dihydrochloride)

HisPur™ Ni-NTA Resin Thermo Scientific™

Thermo Scientific HisPur Ni-NTA Resin is a high-capacity, high-performance nickel-IMAC resin for routine affinity purification of His-tagged fusion proteins.

Features of HisPur Ni-NTA Resin:

High capacity—bind up to 60 mg of 6xHis-tagged protein per milliliter of resin
Versatile—purify proteins using native or denaturing conditions
Compatible—use with Thermo Scientific Cell Lysis Reagents and a variety of buffer additives
Cost-effective—reuse the same batch of resin at least five times
Easy to use—pre-formulated buffers available for kit formats
Flexible—available in multiple formats including bulk resin, spin columns, chromatography cartridges and 96-well filter plates

The specially prepared support consists of beaded agarose derivatized with the nitrilotriacetic acid (NTA) chelation moiety and loaded with divalent nickel ions (Ni2+). The immobilized metal affinity chromatography (IMAC) resin provides exceptional binding capacity and performance for recombinant His-tagged protein purification.

The expression and purification of recombinant proteins is central to protein regulation, structure and function studies. The majority of recombinant proteins are expressed as fusions with short affinity tags, the most popular being the polyhistidine (6xHis) tag. The method used to purify recombinant His-tagged proteins is immobilized metal affinity chromatography (IMAC), consisting of chelating resins charged with either nickel or cobalt ions that coordinate with the histidine side chains.

HisPur Ni-NTA Resin effectively purifies high levels of overexpressed His-tagged fusion proteins from bacterial lysates, such as those that are attained with Thermo Scientific B-PER Bacterial Protein Extraction Reagents. The resin performs well in batch-binding and spin-column procedures at a variety of scales. Performance equals or exceeds popular Ni-NTA resins from other suppliers. HisPur Ni-NTA Resin is a high-quality, stable and resilient affinity support. Tests confirm that no decrease in performance occurs after at least five repeated uses. These data indicated that the resin is highly resistant to structural degradation or nickel ion leaching during normal use.

HisPur Ni-NTA Resin and HisPur Cobalt Resin are alternative forms of IMAC, the former using nickel and the latter using cobalt as the chelated metal ion responsible for His-tag binding. Ni-NTA resins have been the most common IMAC resin choice for 6xHis-tag protein purifications because of the four metal-binding sites on the chelate, which enables high-protein binding and low-metal ion leaching. Cobalt binds less strongly and therefore more discriminantly, enabling greater purity but usually less yield in His-tagged protein purification.

Available Formats:
Resin Slurries—crosslinked 6% beaded agarose; 10 mL, 100 mL, 500 mL bottles
Spin Columns—0.2 mL (microcentrifuge), 1 mL, 3 mL columns
Purification Kits—complete kits in all three column sizes
Chromatography Cartridges—learn more and see HisPur Chromatography Cartridge data
96-well Spin Plates

Related Products
HisPur™ Ni-NTA Spin Columns, 0.2 mL
HisPur™ Ni-NTA Spin Columns, 1 mL
HisPur™ Ni-NTA Spin Columns, 3 mL
HisPur™ Ni-NTA Chromatography Cartridges, 1 mL
HisPur™ Ni-NTA Superflow Agarose

EasyPep™ Mini MS Sample Prep Kit Thermo Scientific™

The Thermo Scientific EasyPep Mini MS Sample Prep Kit provides pre-formulated reagents and a robust method for the preparation of high-quality samples for mass spectroscopy (MS) analysis in less than three hours.

Features of the EasyPep Mini MS Sample Prep Kit include:
Complete—includes pre-formulated reagents for lysis through digestion, peptide clean-up columns, and an optimized protocol for up to 20 samples
Optimized—streamlined protocol and reagents minimize the number of steps and time time needed to process samples
Flexible—reagents and protocol have been verified using cells, plasma, and tissue samples for 10 to 100 µg samples
Time-saving—sample processing time reduced from more than one day to less than three hours
Compatible—final preparation is ready for direct MS analysis and other downstream applications, including TMT labeling

The EasyPep Mini MS Sample Prep Kit enables efficient and reproducible processing of cultured mammalian cells and tissues for proteomic MS analysis. The kit contains pre-formulated buffers, MS-grade enzyme mix, peptide clean-up columns, and an optimized protocol to generate MS-compatible peptide samples in less than three hours. The kit is optimized to process protein samples from 10–100 µg with a high yield of MS-ready peptides.

The sample preparation of peptides for MS analysis is complex, with numerous steps and varied protocols, resulting in sample variability in both quality and quantity. This kit has been designed to improve reproducibility while saving hands-on and processing time. The number of steps and processing time have been reduced through the addition of Universal Nuclease to reduce viscosity from nucleic acids (replacing sonication), a rapid 'one pot' reduction/alkylation solution for cysteine modification (carbamidomethylation, + 57.02), and a trypsin/Lys-C protease mix for more complete digestion. In addition, the kit includes Peptide Clean-up columns and buffers to prepare detergent-free peptide samples for MS analysis. The optimized reagents and protocol produce high-quality peptides that are compatible with TMT labeling and other downstream applications, or are ready for MS analysis.

Related products
Pierce Colorimetric Peptide Quantitation Assay
Pierce Trypsin/LysC Protease Mix, MS-Grade
TMT10plex Label Reagent Set

Tween™ 80 Surfact-Amps™ Detergent Solution Thermo Scientific™

Thermo Scientific Tween-80 Surfact-Amps Detergent Solution is a highly-purified Tween™ 80 detergent stabilized as a 10% solution (w/v) and packaged under nitrogen in glass ampules or non-leaching HDPE bottles, ensuring it's stability and eliminating the accumulation of peroxides and degradation products.

Features of Tween-80 Surfact-Amps Detergent Solution:

Tween 80—a popular nonionic detergent for use in ELISA, Western blotting and other immunoassay PBS or TBS wash buffers
Accurate—precise 10% detergent solution in ultrapure water
Easy-to-use—solution is simple to dispense and dilute for use
Exceptionally pure—less than 1.0µeq/mL peroxides and carbonyls
Stable—packaged under inert nitrogen gas in glass ampules or HDPE bottles

Properties of Tween 80:
• Molecular Weight: 1310g
• Detergent Class: Nonionic polyoxyethylene surfactant
• Aggregation Number: 60
• Micelle Molecular Weight: 76,000g
• Critical Micelle Concentration (CMC): 0.012 mM (0.0016%, w/v)
• Cloud Point: Unknown
• Dialyzable: No

Specifications for Tween 80 Surfact-Amps Detergent Solution:
• Visual: Slightly hazy to cloudy, colorless solution, free of particulates; may form layers.
• Concentration: 10.0±1.0%
• Oxidants: ≤1.0µeq/mL
• Carbonyls: ≤1.0µeq/mL
• Suspended Solids: Residue present must not exceed Residue Reference.

Related Products
Surfact-Amps™ Detergent Sampler

Streptavidin, Allophycocyanin, crosslinked, conjugate Invitrogen™

Streptavidin is a bacterially derived biotin-binding protein that reportedly exhibits less nonspecific binding than avidin. Allophycocyanin is an intensely bright phycobiliprotein with a broad absorption profile that peaks at ~650 nm, and a fluorescence emission maximum of ~660 nm.

View a selection guide for all streptavidin RPE, APC, and tandem conjugates.

Hoechst 33342 Solution (20 mM) Thermo Scientific™

Thermo Scientific Pierce Hoechst 33342 Fluorescent Stain is a high-quality solution of Hoechst dye for fixed- and live-cell fluorescent staining of DNA and nuclei in cellular imaging techniques.

Features of Hoechst 33342 Fluorescent Stain:

Hoechst dye—blue fluorescent stain specific for DNA (i.e., nuclei of eukaryotic cells)
Convenient—provided as an easy-to-use Hoechst dye solution (20 mM)
Cellular imaging—cell-permeable dye is effective for fixed-cell and live-cell staining
Counterstain—ideal for use alongside detection of specific targets with fluorescent antibodies for fluorescence microscopy or high-content screening (HCS)

Hoechst 33342 (2'-[4-ethoxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5'-bi-1H-benzimidazole trihydrochloride trihydrate) is a cell-permeable DNA stain that is excited by ultraviolet light and emits blue fluorescence at 460 to 490 nm. Hoechst 33342 binds preferentially to adenine-thymine (A-T) regions of DNA. This stain binds into the minor groove of DNA and exhibits distinct fluorescence emission spectra that are dependent on dye:base pair ratios.

Properties of Hoechst Fluorescent Dye
As a counterstain in fluorescent imaging, Hoechst dye is compatible with antibodies and other probes labeled with fluorescein and rhodamine dyes, as well as with Thermo Scientific DyLight Fluors. The stable 20 mM aqueous stock solution is essentially ready for use.

Hoechst 33342 is used for specifically staining the nuclei of living or fixed cells and tissues. This stain is commonly used in combination with 5-bromo-2'-deoxyuridine (BrdU) labeling to distinguish the compact chromatin of apoptotic nuclei, to identify replicating cells and to sort cells based on their DNA content. Hoechst 33342 and propidium iodide are frequently used together for simultaneous flow cytometric and fluorescence imaging analysis of the stages of apoptosis and cell-cycle distribution.

SM(PEG)12 (PEGylated, long-chain SMCC crosslinker) Thermo Scientific™

Thermo Scientific Pierce SM(PEG)n is a series of amine-to-sulfhydryl crosslinkers that differ in length from 17.6 to 95.2 angstroms as a result of polyethylene glycol spacer arms containing n equals 2 to 24 ethylene glycol units.

Features of SM(PEG)12:

Reactive groups: NHS ester and maleimide
Reactive toward: amino and sulfhydryl groups
• 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 performing controlled, two-step protein conjugations (see Sulfo-SMCC)

SM(PEG)n NHS- and maleimide-activated PEG compounds for crosslinking between primary amines (NH2) and sulfhydryl (SH) groups in proteins and other molecules. A complete set of compounds are offered, each having the same heterobifunctional structure (NHS-PEGn-Maleimide) but differing in the number of discrete ethylene glycol units ( n = 2, 4, 6, 8, 12 or 24). The N-hydroxysuccinimide ester (NHS) group reacts specifically and efficiently with lysine and N-terminal amino groups at pH 7-9 to form stable amide bonds. The maleimide group reacts with reduced sulfhydryls at pH 6.5-7.5 to form stable thioether bonds.

Alternative Names for SM(PEG)n:
• NHS-dPEG-Mal
• Mal-PEG NHS ester
• NHS-PEO-Maleimide
• Succinimidyl-dPEG-maleimide
• Succinimide-Maleimide PEG

Why use crosslinkers with polyethylene glycol (PEG) spacer arms?
PEG-containing reagents have been used to modify proteins to provide specific advantages. Protein PEGylation can improve the stability of the modified protein, protect it from proteolytic digestion, increase its half life in a biological application, mask it from causing an immunogenic response, decrease its antigenicity or potential toxicity, improve its solubility, diminish the potential for aggregation, and minimize interference for both in vitro and in vivo applications. Polyethylene glycol has these effects because it is nontoxic, nonimmunogenic, hydrophilic, water soluble and highly flexible.

Advantages of discrete-length polyethylene glycol compounds:
These reagents are specially synthesized, resulting in homogeneous compounds of defined molecular weight, characterized by discrete chain lengths, providing a greater ability to optimize and characterize surface protein modifications. Typical preparations of PEG compounds are a heterogeneous mixtures composed of a distribution of chain lengths with a specified average molecular weight or approximate number of PEG subunits.

Related Products
SM(PEG)6 (PEGylated, long-chain SMCC crosslinker)
SM(PEG)8 (PEGylated, long-chain SMCC crosslinker)
SM(PEG)24 (PEGylated, long-chain SMCC crosslinker)

MembranePro™ Functional Protein Support Kit Invitrogen™

For customers studying GPCRs and other membrane proteins, MembranePro™ is the ready-to-use system that delivers enriched, functional membrane proteins efficiently and reliably. Benefits of MembranePro™ include:

• Proteins are displayed on human (or other mammalian) cell membranes
• Cellular quality control and mammalian posttranslational processing helps produce functional protein
• Proteins bud off as lipoparticles and are easily collected from the culture medium
• Lipoparticles are enriched with expressed receptors

MembranePro™ workflow is less labor intensive in comparison to traditional production of membrane fractions. Briefly, the MembranePro™ protocol allows you to:

1. Clone your gene of interest using a TOPO® vector
2. Transfect with Lipofectamine™ 2000 and MembranePro™ Reagent into 293FT cells
3. Harvest lipoparticles 48h post-transfection, concentrate with MembranePro™ Precipitation Mix
4. Store lipoparticles at -80 C or proceed to downstream assays

MembranePro™ products are offered in two configurations – as an expression kit (TOPO® vector, Lipofectamine™ 2000, MembranePro™ Precipitation Mix, MembranePro™ Reagent, 293FT cells) and as a support kit (Lipofectamine™ 2000, MembranePro™ Precipitation Mix, MembranePro™ Reagent). The expression kit is only available in a 10 reaction size; the support kit is available in 10, 60 and 600 reaction sizes.
Results per page
    spinner