Principles of Biochemistry (2+1)

3.3.4.2 Agarose

Agar is a heterogeneous mixture of two classes of polysaccharide: agaropectin and agarose. Although both polysaccharide classes share the same galactose-based backbone, agaropectin is heavily modified with acidic side-groups, such as sulfate and pyruvate. The neutral charge and lower degree of chemical complexity of agarose make it less likely to interact with biomolecules, such as proteins.

Uses: Gels made from purified agarose have a relatively large pore size, making them useful for size-separation of large molecules, such as proteins or protein complexes >200 kilo Daltons, or DNA fragments >100 base pairs. Agarose can be used for electrophorotic separation in agarose gelelectrophoresis or for column-based gel filtration.