Characteristics of Enzyme
Enzymes are biocatalysts produced in the protoplasm. They are synthesized in the cell. The basic properties of enzymes are:
- Most of the enzymes are proteinaceous in nature. They are macromolecules of globular proteins with higher molecular weight. They may entirely consist of protein e.g. amylase or pepsin or may contain, along with protein, a non-protein part. E.g. holoenzyme.
- They react with both acidic and alkaline substances due to the presence of protein as their major part.
- Enzymes generally act within the living cell where they have been produced but sometimes they diffuse out of the cell and perform catalytic function out side the cell or in other cells. An enzyme which acts within the same cell is called intracellular enzymes or endoenzyme and the enzyme which acts outside the cell is called exoenzyme.
- They are specific in their nature and their action.
- Their molecules are much greater in size than the substrate.
- They have particular sites to react with the substrates called active site.
- They are biocatalyst, which speed up the rate of reaction. They are required in very small quantities which are capable of bringing about a change in large amounts of substrates.
- Enzyme activities can be accelerated by certain ions or salts called activators e.g. Mn, Ni, Mg, Cl, etc. ix) Enzymes activities can be inhibited by certain factors called inhibitors e.g. substrate concentration, enzyme concentration, pH.
- They are heat sensitive i.e. they are thermolabile and pH sensitive i.e. they work on specific pH.
- They remain chemically unchanged during and after the chemical reactions.