Many enzymes require non – protein components called co – factors for their efficient activity. Co – factors may vary from simple inorganic ions to complex organic molecules.
They are of three types:
1. Inorganic ions, prosthetic groups and coenzymes.
2. Holoenzyme – active enzyme with its non – protein component.
3. Apoenzyme – the inactive enzyme without its non – protein component.
Inorganic ions help to increase the rate of reaction catalysed by enzymes.
Example: Salivary amylase activity is increased in the presence of chloride ions.
Prosthetic groups are organic molecules that assist in catalytic function of an enzyme. Flavin adenine dinucleotide (FAD) contains riboflavin(vit B2), the function of which is to accept hydrogen. ‘Haem’ is an iron – containing prosthetic group with an iron atom at its centre. Coenzymes are organic compounds which act as cofactors but do not remain attached to the enzyme. The essential chemical components of many coenzymes are vitamins. Eg. NAD, NADP,Coenzyme A, ATP.
