What are enzymes?

Answer

Enzymes are biological catalysts. Each biological system requires a different enzyme. Thus, as compared to conventional catalysts, enzymes are very specific and efficient in their action. They are required in only small quantity and work at optimum temperature `(310 K)` and `pH(7.4)` under one atmospheric pressure. Chemically, they are globular proteins. However, some enzymes are also associated with some non-protein compenent called the cofactor for their activity. Cofactors are of two types :
(a) Inorganic ions such as `Zn^(2+),Mg^(2+),Mn^(2+),Fe^(2+),Cu^(2+),CO^(2+)`, etc
(b) Organic molecules. These are also of two types :
(i) Coenzymes. These are usually derived from vitamins such as thaimine, riboflavin, niacin, etc. They are loosely held to the protein and can be easily separated by dialysis.
(ii) Prosthetic group. These are also derived from vitamins such as biotin but are tightly held to the protein molecule by covalent bonds. They can be separated only by careful hydrolysis.