CM Agarose Bead – Catalog #B2025394

CM Agarose Bead (Catalog #B2025394) is supplied as 25 mL of a cation exchange chromatography resin consisting of agarose beads with carboxymethyl (–CH₂–COO⁻) functional groups. The negatively charged carboxymethyl groups bind positively charged proteins (those with net positive charge at the working pH) while allowing negatively charged proteins and other molecules to flow through. The high porosity of the agarose matrix provides excellent flow properties, low back-pressure, and high protein binding capacity, making it suitable for both batch purification and gravity-flow column chromatography.

Scientific Overview

Agarose is a natural polymer derived from red algae and is widely used as a chromatography matrix because of its chemical stability, high porosity, low non-specific adsorption, and excellent compatibility with proteins and other biomolecules. Covalent attachment of carboxymethyl groups (–CH₂–COOH) to the agarose backbone creates a weakly acidic cation exchanger that functions over a broad pH range (typically pH 4–9). The ionizable carboxyl groups are negatively charged at neutral pH, binding proteins with a net positive charge (high pI, basic proteins) while allowing neutral and negatively charged molecules to pass through or be eluted at lower salt concentrations.

The agarose matrix's high porosity (large pore size) allows efficient diffusion of large molecules, including intact antibodies, enzymes, and multi-subunit complexes, into and out of the resin. This, combined with the high flow rates and low back-pressure typical of agarose chromatography, makes CM Agarose ideal for both analytical purifications and preparative-scale protein separations.

Key applications include:

• Capture and concentration of basic enzymes and antibodies from crude extracts or fermentation broths
• Purification of recombinant proteins expressed in bacteria or eukaryotic cells
• Separation of protein isozymes and variants based on pI differences
• Batch or gravity-flow chromatography for quick, efficient protein purifications
• Removal of contaminants and impurities in protein purification workflows
• Laboratory-scale and preparative protein fractionation

Usage & Handling Guidance

Before use, allow the resin to settle and remove excess storage buffer by decanting or using a peristaltic pump. For batch chromatography, mix the resin slurry with your protein sample and allow binding to occur, then separate the resin from the flow-through by centrifugation or gravity settling. For column chromatography, pack the resin into a Ecad-style glass column or plastic chromatography column under gravity flow, then load the protein sample and elute with a salt gradient (e.g., 0–1 M NaCl) to recover bound proteins.

• Equilibration: Wash the resin with at least 10 column volumes of binding buffer (typically 20 mM Tris or phosphate, pH 7–8) before loading the sample.
• Binding pH: The carboxymethyl groups are ionized at pH >4, so perform binding at pH 6–8 for optimal charge on both the resin and the target protein.
• Salt gradient elution: Bind at low salt (~0 M NaCl) and elute with a linear gradient to 1 M NaCl or higher, depending on the protein's pI. Proteins with higher pI values will bind more strongly and require higher salt for elution.
• Flow rate: Agarose is pressure-tolerant and allows flow rates of 2–5 mL/min for an 10 mm diameter column without excessive back-pressure. Faster flow rates can be used for initial sample loading.
• Regeneration and storage: After use, wash with 1 M NaCl, then water, then storage buffer (typically 20% ethanol in PBS). The resin can be stored at 2–8°C or room temperature in storage buffer for extended periods.

What You Get

• 25 mL of CM Agarose cation exchange resin
• A high-capacity, high-flow chromatography matrix for protein purification
• Suitable for batch and gravity-flow column applications
• For research use only (RUO)

Why Researchers Choose It

• High porosity for efficient binding and elution of large proteins
• High flow rate with low back-pressure, ideal for gravity-flow columns
• Excellent protein binding capacity and selectivity
• Compatible with standard chromatography hardware
• Cost-effective and robust for laboratory-scale purifications
• Proven track record in enzyme and antibody purification

Frequently Asked Questions (FAQ)

• Which proteins bind to CM Agarose?
  Proteins with a net positive charge (pI >pH of the buffer) will bind. CM Agarose works best for basic proteins (pI >7) at neutral pH. Proteins with pI <7 will pass through and can be recovered in the flow-through.
• How do I elute bound proteins?
  Apply a linear salt gradient (e.g., 0–1 M NaCl) at the same pH used for binding. Proteins elute in order of increasing charge (lower pI first). Collect fractions and assay for your protein of interest.
• What column size should I use?
  For preparative work, use a column diameter such that the resin bed height is 5–20 cm. A 1 cm diameter column with 10 cm bed height contains ~7.9 mL of settled resin and is suitable for 5–50 mg of protein, depending on the target and contaminants.
• Can I use this resin for FPLC or HPLC?
  CM Agarose is designed for gravity-flow and low-pressure chromatography. It can withstand moderate pressure, but for high-resolution, high-speed separations, use smaller-bead, higher-density ion exchange resins optimized for FPLC or HPLC.
• How do I pack the column?
  Prepare a slurry of the resin in binding buffer, pour into a plastic or glass column, and allow to pack under gravity. Alternatively, gently apply low pressure (e.g., 0.5 bar) with a peristaltic pump to speed up packing. Avoid air bubbles; tap the column gently if needed to remove them.
• How long does the resin last?
  With proper handling and regeneration, CM Agarose can be used for dozens of purifications over months or years. Store in 20% ethanol at 2–8°C or room temperature to prevent microbial growth.
• Can I get a TDS or COA?
  Yes. Request a quote or contact us and we will provide available lot documentation, binding capacity data, and pH range specifications.

References

• Ameis D, Merkel M, Eckerskorn C, Greten H. Purification, characterization and molecular cloning of human hepatic lysosomal acid lipase. Eur J Biochem. 1994;219(3):905-14.
• Maharjan P, Hearn MT, Jackson WR, De Silva K, Woonton BW. Development of a temperature-responsive agarose-based ion-exchange chromatographic resin. J Chromatogr A. 2009;1216(50):8722-9.
• Sauer DG, Mosor M, Frank AC, Weiß F, Christler A, Walch N, Jungbauer A, Dürauer A. A two-step process for capture and purification of human basic fibroblast growth factor from E. coli homogenate: Yield versus endotoxin clearance. Protein Expr Purif. 2019;153:70-82.