Agarose (C15-1291-105)

General description

Agarose contains β-D-galactose and 3,6-anhydro-α-L-galactose, linked by glycosidic bonds β(1-4).

Application

Agarose is the most popular medium for immunoelectrophoresis because of the large pore size for rapid diffusion and for low background staining by Coomassie Blue G stain. The low EEO and high gel strength is specifically selected and tested for immunoelectrophoresis and immunodiffusion.

Preparation Note

Gel Preparation:
1. Prepare a 1% agarose solution (sufficient for 10 gels 85 mm x 100 mm, 1-1.5 mm thick) by mixing 1.5 g agarose (Catalog No. A4679) in 150 mL of prepared barbital buffer and heat in a boiling water bath until completely dissolved.
2. To prepare one gel, pour 14 mL of agarose solution onto the hydrophilic side of a level, well supported 85 mm x 100 mm sheet of Electrophoresis Film for Agarose Gels (Catalog No. E0264). Pour from the center of the sheet toward its edges forming an even layer of agarose 1-1.5 mm thick.
3. Allow the gels to harden for one hour at 4 °C before using or store at 0-5 °C in an appropriate, plastic wrapped container.

Analysis Note

The following is a list of properties associated with our agaroses:
Sulfate content - used as an indicator of purity, since sulfate is the major ionic group present.
Gel strength - the force that must be applied to a gel to cause it to fracture.
Gel point - the temperature at which an aqueous agarose solution forms a gel as it cools. Agarose solutions exhibit hysteresis in the liquid-to-gel transition - that is, their gel point is not the same as their melting temperature.
Electroendosmosis (EEO) - a movement of liquid through the gel. Anionic groups in an agarose gel are affixed to the matrix and cannot move, but dissociable counter cations can migrate toward the cathode in the matrix, giving rise to EEO. Since electrophoretic movement of biopolymers is usually toward the anode, EEO can disrupt separations because of internal convection.