Alexa Fluor® 405 NHS Ester (Succinimidyl Ester)

Catalog number: A30000

Molecular Probes™  Related applications: Labeling Chemistry | Protein Labeling & Crosslinking

Error loading your content!

  Catalog number
Select a plan
Unit size
Price ({{currency}}) Qty
{{product.sku}} {{product.sku}}
also known as {{product.formattedSku}} 
{{product.availability.message}}
Pro add-ons

Your on-site stock

›› {{supplyCenter.scName}}({{scProduct.stockOnHand}} In stock)
›› {{supplyCenter.scName}}(Out of stock)
›› {{supplyCenter.scName}}
This item is not currently available on-site. Depending on your Supply Center settings you may be able to add the item to cart above else use the Order Non-Stocked Items' tab on the Supply Center home page.
Back to top

Description

Alexa Fluor™ 405 is a blue-fluorescent dye optimal for use with the 405 nm violet laser. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor™ 405 dye is water soluble and pH-insensitive from pH 4 to pH 10.

View all Alexa Fluor® 405 dye products.

View the Fluorophore Selection Guide.

The NHS ester (or succinimidyl ester) of Alexa Fluor™ 405 is the most popular tool for conjugating this dye to a protein or antibody. NHS esters can be used to label to the primary amines (R-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting Alexa Fluor™ conjugate will exhibit brighter fluorescence and greater photostability than the conjugates of other spectrally similar fluorophores.

Detailed information about this AlexaFluor™ NHS ester:

Fluorophore label: Alexa Fluor™ 405 dye
Reactive group: NHS ester
Reactivity: Primary amines on proteins and ligands, amine-modified oligonucleotides
Ex/Em of the conjugate: 400/424 nm
Extinction coefficient: 35,000 cm-1M-1
Spectrally similar dyes: Pacific Blue
Molecular weight: 1028.3

Typical conjugation reaction
You can conjugate amine-reactive reagents with virtually any protein or peptide (the provided protocol is optimized for IgG antibodies). You can scale the reaction for any amount of protein, but the concentration of the protein should be at least 2 mg/mL for optimal results. We recommend trying three different degrees of labeling, using three different molar ratios of the reactive reagent to protein.

The Alexa Fluor™ NHS ester is typically dissolved in high-quality anhydrous dimethylformamide (DMF) or dimethylsulfoxide (DMSO) (D12345), and the reaction is carried out in 0.1–0.2 M sodium bicarbonate buffer, pH 8.3, at room temperature for 1 hour. Because the pKa of the terminal amine is lower than that of the lysine epsilon-amino group, you may achieve more selective labeling of the amine terminus using a buffer closer to neutral pH.

Conjugate purification
Labeled antibodies are typically separated from free Alexa Fluor™ dye using a gel filtration column, such as Sephadex™ G-25, BioGel™ P-30, or equivalent. For much larger or smaller proteins, select a gel filtration media with an appropriate molecular weight cut-off or purify by dialysis. We offer several purification kits optimized for different quantities of antibody conjugate:
• Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
• Antibody Conjugate Purification Kit for 20-50 µg (A33087)
• Antibody Conjugate Purification kit for 50-100 µg (A33088)

Learn more about protein and antibody labeling
View a selection guide for all Protein Labeling Kits.

View a selection guide for all Antibody Labeling Kits.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.
For Research Use Only. Not for use in diagnostic procedures.

Specifications

Label or Dye: Alexa Fluor™ 405
Chemical Reactivity: Amine
Detection Method: Fluorescent
Excitation⁄Emission (nm): 401⁄421
Flow Cytometer Laser Lines: 405
Form: Solid
Product Size: 1 mg
Solubility: DMSO (Dimethylsulfoxide)
Shipping Condition: Room Temperature

Contents & storage

Contains 1 vial (1 mg).

Store in freezer (-5 to -30°C) and protect from light.

Documents

Manuals & protocols

Recommended products