The most commonly employed matrices are agarose, celluloses and polyacrylamides. Sepharose, an agarose, is available commercially as beads, is highly hydrophilic and is generally inert to microbial attack. Sepharose is activated by treating it with chloroformates, carbodiimides, glutaraldehyde or other compounds.

Gluteraldehyde is a bifunctional reagent. It exists as an equilibrium mixture of monomer and oligomers. It can be used to covalently bind the enzyme molecules or, alternatively, it can be used to cross link enzyme molecules. In cross linking, each bifunctional reagent molecule binds to two enzyme molecules; ultimately, a network of enzyme molecules linked together is produced.

This can be markedly reduced as follows. The enzyme is immobilized in the presence of saturating concentration of its substrate or a competitive inhibitor (such inhibitors bind to the active site).

In such a situation, the active site is occupied and kept in the correct conformation while immobilization takes place; this minimise the involvement of active site as well as incorrect orientation of the enzyme molecules during immobilization.