Enzymes may be described as biocatalysts synthesised by living cell.
They are protein in nature, colloidal and thermoliable in character and specific in their action.
Enzymes regulate the rate of biochemical reactions without being utilized in these reactions.
Enzymes accelerate biochemical reactions without affecting equilibrium.
The term enzyme was coined by w.kuhne.
The study of enzymes is called Enzymology.
Edward Buchner who is considered as father of enzymology, accidentally discovered that a juice extracted using the yeast cells could bring out fermentation.
He coined the term Zymase to designate the active principle involved in fermentation.
James B. Sumner, isolated the enzyme urease from Jack bean (Canavalia ensiformis) in pure crystalline form, and established the protein nature of enzymes.
John Northrop and his associates isolated pepsin and trypsin in crystalline form.
So far more than 200 enzymes have been purified and characterised.
Endoenzymes and Exoenzymes:
Enzymes which act with in the cells in which they are synthesized are called Endoenzymes. Most of the enzymes are endoenzymes Eg:
Enzymes which act outside the cells of their origin are called exo-enzymes.