Low Density Glyoxal 4 Agarose (4% Cross-linked) – Catalog #B2025402

Low Density Glyoxal 4 Agarose (Catalog #B2025402) is a pre-activated affinity chromatography resin on a 4% cross-linked agarose backbone bearing aldehyde (glyoxal) functional groups at a deliberately low density. The glyoxal groups react directly with the primary amino groups of lysine residues in proteins and peptides, forming reversible Schiff bases that can be reduced with sodium borohydride or sodium cyanoborohydride to give stable secondary amine linkages. The low density of reactive groups minimizes steric hindrance and allows controllable, stoichiometric coupling.

Scientific Overview

Glyoxal-activated agarose is widely used for covalent immobilization because glyoxal groups (aldehydes) react readily and specifically with the primary amino groups of lysine residues. The Schiff base formed between an aldehyde and a primary amine is initially reversible; however, reduction with sodium borohydride or sodium cyanoborohydride converts it to a stable secondary amine bond (C−N), creating a permanent, covalent linkage. This chemistry is gentler than some alternatives (e.g., N-hydroxysuccinimide esters) and allows high-density coupling without protein denaturation. The low density of glyoxal groups on this resin means fewer potential coupling sites per unit volume, reducing cross-linking and aggregation and enabling more controlled, monovalent coupling when desired.

Key applications include:

• Covalent immobilization of enzymes for affinity chromatography or biocatalysis
• Coupling of antibodies or ligands for immunoaffinity purification
• Development of enzyme reactors and continuous bioreactors
• Preparation of diagnostic and research assay matrices
• Protein stabilization through multipoint covalent attachment

Usage & Handling Guidance

Store the resin at 2–8°C in its original packaging. Before coupling, inspect the resin for color; excessive yellowing may indicate hydrolysis of glyoxal groups. Pre-activate by incubating with your target protein or ligand at room temperature or 4°C in an appropriate buffer (e.g., PBS, pH 7.0–8.0, or 0.1 M sodium carbonate pH 9.0). Coupling time is typically 2–4 hours or overnight. After coupling, reduce the Schiff base with sodium borohydride (NaBH₄) or sodium cyanoborohydride (NaCNBH₃) for maximum stability, following safety precautions for these reagents.

• Coupling buffer: pH 7–9 is typical; higher pH (8.5–9.0) accelerates Schiff base formation.
• Protein concentration: 1–10 mg/mL is standard; start with empirical optimization.
• Reduction: Use NaBH₄ in ethanol or NaCNBH₃ in pH 7 buffer, following the manufacturer's instructions.
• Washing: After coupling and reduction, wash thoroughly to remove unreacted protein and excess reagents.

What You Get

• 25 mL of low-density glyoxal agarose (4% cross-linked)
• Pre-activated resin ready for direct protein or ligand coupling
• Enough material for multiple immobilization experiments
• For research use only (RUO)

Why Researchers Choose It

• Specific, covalent coupling via lysine residues
• Low aldehyde density reduces protein aggregation and cross-linking
• Mild, generally non-denaturing chemistry
• Stable secondary amine bonds after reduction
• Versatile for enzymes, antibodies, and small ligands

Frequently Asked Questions (FAQ)

• What is the difference between glyoxal and other activated agaroses?
  Glyoxal (aldehyde) reacts specifically and reversibly with lysine, forming Schiff bases that are stabilized by reduction. This is gentler than some other chemistries (e.g., N-hydroxysuccinimide esters) and allows controlled coupling.
• Do I have to reduce the Schiff base?
  For maximum stability, yes. The Schiff base is reversible; reduction with NaBH₄ or NaCNBH₃ converts it to a stable secondary amine. For transient applications, reduction may not be necessary.
• How do I know if the glyoxal groups have reacted?
  A color change from faint yellow to colorless or white indicates conversion of aldehydes to Schiff bases. After reduction, the resin should be pale/white.
• What proteins can be coupled?
  Any protein or peptide with accessible lysine residues can be coupled. Optimization may be needed for very small peptides or lysine-poor proteins.
• Can I get a COA or technical information?
  Request a quote or contact us and we will provide available lot documentation.

References

• López-Gallego F, Montes T, Fuentes M, Alonso N, Grazu V, Betancor L, Guisán JM, Fernández-Lafuente R. Improved stabilization of chemically aminated enzymes via multipoint covalent attachment on glyoxyl supports. J Biotechnol. 2005;116(1):1-10.
• Knödler M, Rühl C, Opdensteinen P, Buyel JF. Activated Cross-linked Agarose for the Rapid Development of Affinity Chromatography Resins - Antibody Capture as a Case Study. J Vis Exp. 2019;(150).