Copper(II) sulfate (CuSO4)
"baseclick-grade" copper catalyst in high quality for optimal yield
| Size | Catalog No. | Price |
|---|---|---|
| 5 x 10 mg | BCMI-004-10x5 | € 55,00 |
| 10 x 10 mg | BCMI-004-10x10 | € 90,00 |
Chemical Properties
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Molecular Formula
CuSO4
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Shelf Life
12 months unopened after receipt
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Storage Conditions
RT, dry, inert gas
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Molecular Weight
159.6 g/mol
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Purity
≥ 98% (iodometric)
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Physical State
light green to grey fine powder
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CAS Number
7758-98-7
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Solubility
aqueous media
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Preparation/Handling
Water-soluble copper(I) source for click reactions after reduction (e.g. by using BCMI-005)
Product Information
Water-soluble copper source for biomolecule-friendly click reactions
Copper(II) sulfate (CuSO₄) is a widely used copper source for copper-catalyzed azide–alkyne cycloaddition (CuAAC), the first reaction defined as “Click Chemistry” and still the most applied click reaction today. Its full water solubility makes CuSO₄ the catalyst of choice for reactions in aqueous media, particularly for experiments involving cell culture or sensitive biomolecules, which can be compromised in water/organic solvent mixtures.
Catalytic Mechanism
CuAAC requires a Cu(I) species as active catalyst. When using CuSO₄, a reducing agent such as sodium ascorbate is typically added to convert Cu(II) to Cu(I). Sodium ascorbate ensures efficient reaction initiation under mild conditions.
Key Considerations
- Use of Copper-Chelating Ligands: To prevent side reactions, a water-soluble ligand such as THPTA is highly recommended.
- Purity of Reactants: High-purity alkyne and azide reactants are essential for optimal performance. baseclick provides and tests reagents specifically for CuAAC workflows.
- Buffer Compatibility: Avoid EDTA-containing buffers and DEPC-treated water, as these chelate copper and inhibit the reaction.
Applications
- mRNA Labeling: CuSO₄-based CuAAC protocols for RNA modification under aqueous conditions.
- Oligonucleotide Labeling: Efficient conjugation for nucleic acid research and bioconjugation workflows.
Protocols
baseclick offers validated protocols for CuAAC using CuSO₄, including applications for mRNA and oligonucleotide labeling. These serve as starting points; adjust conditions for different concentrations or reaction partners to achieve optimal results.
Copper(II) sulfate (CuSO4) is one of the potential copper sources as catalyst to perform copper catalyzed alkine-azide cycloaddition (CuAAC). CuAAC was the first descript reaction meeting the criteria for “Click Chemistry” and remains the most widely used click reaction to this day. CuSO4 is fully water-soluble, making it the catalyst of choice for reactions performed in aqueous media, especially for experiments involving cell culture or sensitive biomolecules, which can be degraded or changed in tertiary structure in water/organic solvent mixtures. Since CuAAC reaction requires a Cu(I) species as catalyst, a reducing agent as sodium ascorbate is usually used to create the active catalyst form of copper(II) sulfate. To prevent CuSO4 from catalyzing side reactions the usage of a copper chelating ligand is highly recommended. For copper sulfate a water soluble ligand as THPTA is required as well as highly pure reactants as those provided and tested by baseclick for CuAAC reactions.
To optimize the performance of your reactions, baseclick provides several protocols for the setup of click reactions using CuAAC, including CuSO4-based reaction protocols for mRNA labeling, or Oligo labeling. Please be aware, that this protocol is only meant as a starting point. If other concentrations or reaction partners as mentioned in the protocols are used, please consider varying the conditions in order to obtain the optimal reaction outcome. Please note, that all EDTA containing buffers will interfere with your CuAAC reactions by chelating the catalyst. The usage of DEPC treated water has the same effect.
FAQ
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What is the best catalyst for my reaction?
The optimal catalyst depends on your application and the solvents used. In general, there are three major catalyst systems for copper-catalyzed click reactions that apply the required Cu(I) source:
1) Working in aqueous media: Then we recommend using a CuSO4 based system. To generate the catalytic Cu(I) species, please do not forget to add the necessary sodium ascorbate (BCMI-005) and our water soluble THPTA ligand (BCMI-006). As the sodium ascorbate has restricted stability when dissolved, please prepare this solution always fresh.
2) Working in organic medium (mostly DMSO or click solution): Then we recommend using CuBr (BCMI-001) and TBTA ligand (BCMI-002) for labeling reactions. Please note, that CuBr is sensitive to air. Therefore, we take precautions when aliquoting and sealing this compound. Once opened, please use the compound fast (within a few hours maximum).
3) For small sample amounts from e.g. enzymatic reactions in aqueous media we recommend using our reactor system that is part of our Oligo Link kits. As this catalyst will not dissolve during the reaction and can also be applied in organic media, its handling is very simple as described in the kit user manual. Additionally, the long-term storage is superior compared to the other catalyst systems. -
What is the yield of click reactions?
The nature of click chemistry is that the reactions are fast, efficient and results in high yields. Under optimal conditions, quantitative yields are easily achieved.
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What kind of labels can be clicked?
As it is the nature of click reactions, various groups can be attached to nucleic acids, not constricted to dyes. The only requirement is the use of high quality reagents containing clickable groups.
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Why use CuSO₄ for CuAAC reactions?
CuSO₄ is fully water-soluble, making it the ideal copper source for aqueous CuAAC reactions, especially when working with biomolecules or cell culture systems that cannot tolerate organic solvents.
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How does CuSO₄ become catalytically active?
CuAAC requires Cu(I) as the active catalyst. When using CuSO₄, a reducing agent such as sodium ascorbate is added to convert Cu(II) to Cu(I) under mild conditions.
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Do I need a ligand with CuSO₄?
Yes. To prevent side reactions and stabilize Cu(I), use a water-soluble ligand such as THPTA for optimal performance.
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Which buffers and water types should I avoid?
Avoid EDTA-containing buffers and DEPC-treated water, as they chelate copper and inhibit the reaction. Use double-distilled or HPLC-grade water instead.
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What applications is CuSO₄ best suited for?
CuSO₄ is ideal for mRNA labeling, oligonucleotide labeling, and other bioconjugation workflows performed in aqueous media.
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Does baseclick provide protocols for CuSO₄-based CuAAC?
Yes. We offer validated protocols for mRNA and oligonucleotide labeling using CuSO₄. These serve as starting points and can be adapted to your specific experimental conditions.