11th Class Biology Biomolecules / जैव-अणु Site Of Enzyme Action

All enzymes are produced in the living cells. About 3,000 enzymes have recorded. These are of two types with regard to the site where they act as :

Intracellular enzymes :  Most of the enzymes remain and function inside the cells, They are called the intracellular enzymes or endoenzymes. Some of these enzymes are found in cytoplasmic matrix. Certain enzymes are bound to ribosomes, mitochondria and chloroplast etc.

Extracellular enzymes : Certain enzymes leave the cells and function outside them. They are called the extracellular enzymes or exoenzymes. They mainly include the digestive enzymes. e.g., salivary amylase, gastric pepsin, lysozyme present in tears and nasal secretion.

Rennet tablets with enzyme renin from calf's stomach are widely used to coagulate protein caseinogen for cheese (casein) formation.