Immobilized enzyme

An immobilized enzyme is an enzyme that is attached to an inert, insoluble material. This can provide a higher resistance to changes in condition such as pH or temperature.

Commercial use

Immobilised enzymes can be important for commercial uses as they have many benefits to the cost and processes of the reaction such as:

• Convenience: small amounts of protein dissolve in the reaction so purification of the product is easier.
• Economy: The immobilized enzyme is easily removed from the reaction so it can be recycled. This is useful in the production of lactose-free milk as the milk can be drained from a container leaving the enzyme (lactase) inside for the next batch.
• Stability: Immobilised enzymes normally have a higher thermal and operational stability than the soluble form of the enzyme.
• Safety: In the past, biological washing powders contained proteases and lipases that would break down dirt but also irritate the skin if it was touched - immobilization prevents this from happening

Methods

• Adsorption on glass: The enzyme is attached to a glass bead.
• Covalent bond: The enzyme is bound covalently to a support (such as silica gel).
• Cross-linkage: Multiple enzymes are bound together to create a matrix.
• Affinity-tag binding: Enzymes attached to a surface with protein tags.