Na-Ascorbate

Product Information

High purity, reliable performance, optimized for CuAAC in sensitive biomolecule applications

Na-ascorbate, the sodium salt of ascorbic acid, is the most commonly used reducing agent for performing the copper catalyzed alkyne-azide cycloaddition (CuAAC) with CuSO₄. The CuAAC reaction was the first reaction to meet the criteria for “Click Chemistry” and remains the most widely used click reaction today.

Na-ascorbate is needed to reduce the Cu(II) in CuSO₄ to the catalytic active Cu(I) species necessary for catalyzing the click reaction. This system is ideal for aqueous CuAAC reactions, especially with water-soluble biomolecules in cell culture experiments or with sensitive biomolecules that cannot tolerate organic solvents such as DMSO.

To prevent copper from catalyzing unwanted side reactions, the use of a copper-chelating ligand (e.g., THPTA) is highly recommended. For optimal results, use high-purity reagents such as those provided and tested by baseclick.

CuAAC Reaction Optimization

To optimize the performance of your reactions, baseclick provides several protocols for the setup of click reactions using CuAAC, including Na-ascorbate activated CuSO₄ reaction protocols as for mRNA labeling, or Oligo labeling. These protocols serve as starting points, adjust conditions as needed for different concentrations or reaction partners.

Handling & Storage

• Prepare Na-ascorbate solutions fresh for best results.
• Stock solutions can be stored at –20 °C and diluted before use.
• Do not use solutions that have turned brownish.

Important: Avoid EDTA-containing buffers and DEPC-treated water, as they chelate copper and inhibit the reaction. Use double-distilled water (ddH₂O) or HPLC-grade water instead.

LITERATURE

Rostovtsev, V. V., et al. (2002). A Stepwise Huisgen Cycloaddition Process: Copper(I)-Catalyzed Regioselective “Ligation” of Azides and Terminal Alkynes. Angewandte Chemie International Edition, 41(14), 2596–2599.

https://doi.org/10.1002/1521-3773(20020715)41:14%3C2596::aid-anie2596%3E3.0.co;2-4

Kolb, H. C., Finn, M. G., & Sharpless, K. B. (2001). Click Chemistry: Diverse Chemical Function from a Few Good Reactions. Angewandte Chemie International Edition, 40(11), 2004–2021.

https://onlinelibrary.wiley.com/doi/full/10.1002/1521-3773%2820010601%2940%3A11%3C2004%3A%3AAID-ANIE2004%3E3.0.CO%3B2-5

Hong, V., et al. (2009). Analysis and Optimization of Copper-Catalyzed Azide–Alkyne Cycloaddition for Bioconjugation. Bioconjugate Chemistry, 20(2), 333–338

https://doi.org/10.1002/anie.200905087

Functionalization of the surface of electrospun poly(epsilon-caprolactone) mats using zwitterionic poly(carboxybetaine methacrylate) and cell-specific peptide for endothelial progenitor cells capture, Q. Li et al., 2013, Mater. Sci. Eng., Vol. 33(3), p. 1646-1653.

https://doi.org/10.1016/j.msec.2012.12.074

Synthesis of in situ functionalized iron oxide nanoparticles presenting alkyne groups via a continuous process using near-critical and supercritical water, M. D. de Tercero, 2013, J Supercrit Fluids, Vol. 82, p. 83-95.

https://doi.org/10.1016/j.supflu.2013.06.006