ExtraBind Protein G Agarose Resin – Catalog #B2025428

ExtraBind Protein G Agarose Resin (Catalog #B2025428) is a pre-packed affinity chromatography resin for high-capacity purification of immunoglobulin G (IgG) and other antibodies from serum, cell culture supernatants, and other biological samples. Protein G, derived from Streptococcus, binds the Fc region of antibodies across a broad range of species, enabling species-independent purification without requiring prior knowledge of antibody source.

Scientific Overview

Protein G is a surface protein from Streptococcus (typically S. pyogenes or S. agalactiae) that binds the Fc region of immunoglobulins. Unlike Protein A, which shows species-dependent binding preferences (strong for mouse and human IgG but weak for goat or sheep IgG), Protein G binds broadly across mammalian IgG from most species. The agarose matrix is a cross-linked polysaccharide that provides high physical and chemical stability during repeated use, making it suitable for both gravity-driven and pressure-driven column chromatography. The 6% crosslinking offers a balance between flow rate and mechanical strength.

Key applications include:

• Purification of polyclonal antibodies from animal sera
• Affinity enrichment of monoclonal antibodies from cell culture supernatants
• Removal of non-specific immunoglobulins from biological samples
• Preparation of purified antibodies for diagnostic assays, Western blotting, and immunoprecipitation
• Antibody screening and characterization

Usage & Handling Guidance

The resin can be used in gravity-flow columns or with peristaltic pump systems. Equilibrate with 5–10 column volumes of binding buffer (typically 0.1 M phosphate or 0.1 M Tris, pH 7–8) before loading. Load sample at 1–4 mL/min per mL of resin and collect flowthrough if non-IgG proteins are to be recovered separately. Elute bound antibodies with a mild elution buffer (pH 2.5–3.0, such as 0.1 M citric acid or glycine-HCl) collected into neutralization buffer. The resin can be regenerated with 0.1 M glycine-HCl pH 2.5 for 5–10 minutes, then re-equilibrated.

• Loading: Apply 0.1–10 mg IgG per mL of resin, depending on sample composition and purity requirements.
• Flow rate: 1–4 mL/min per mL of resin for typical column diameters.
• Elution: Use pH 2.5–3.0 buffers; collect in neutralization buffer to immediately restore pH.
• Storage: Keep packed resin at 2–8°C in 20% ethanol or storage buffer supplied by the manufacturer.

What You Get

• 5 mL of Protein G agarose resin, pre-packed or as a slurry
• High binding capacity for IgG across multiple species
• Stable 6% crosslinked agarose matrix for repeated use
• For research use only (RUO)

Why Researchers Choose It

• Species-independent Fc binding covers antibodies from mouse, human, goat, sheep, rabbit, and other mammals
• High capacity and rapid flow rate for large-scale antibody purification
• Stable agarose matrix withstands pH extremes and organic solvents, allowing regeneration and reuse
• Mild elution conditions preserve antibody structure and biological activity

Frequently Asked Questions (FAQ)

• What is the difference between Protein G and Protein A?
  Both bind Fc regions, but Protein A shows strong affinity for human and mouse IgG, while Protein G binds more broadly across mammalian species, including goat and sheep antibodies.
• How much sample can I load?
  Typically 1–10 mg IgG per mL of resin, depending on purity. Request a COA/TDS for lot-specific binding capacity.
• What pH should I use for elution?
  pH 2.5–3.0 is standard; collect into neutralization buffer immediately to restore pH and preserve antibody activity.
• Can the resin be reused?
  Yes. Regenerate by washing with pH 2.5–3.0 buffer for 5–10 minutes, then re-equilibrate with binding buffer.
• How do I set up the column?
  Pour slurry into a gravity or pump column, allow settling, equilibrate with binding buffer, and begin loading your sample.

References

• Cassedy A, O'Kennedy R. Antibody Purification Using Affinity Chromatography. Methods Mol Biol. 2022;2466:3-22.
• Grodzki AC, Berenstein E. Antibody purification: affinity chromatography - protein A and protein G Sepharose. Methods Mol Biol. 2010;588:33-41.
• Fishman JB, Berg EA. Protein A and Protein G Purification of Antibodies. Cold Spring Harb Protoc. 2019;2019(1).
• Darcy E, Leonard P, Fitzgerald J, Danaher M, Ma H, O'Kennedy R. Purification of Antibodies Using Affinity Chromatography. Methods Mol Biol. 2017;1485:305-318.