Enzymes

Definition
Enzymes are a class of proteins which catalyze all types of bio-chemical reaction, such as digestion, respiration, muscular contraction and metabolism.
In all living structures, the biological reactions are catalyzed by Enzymes, even the biosynthesis of enzymes by living things is also catalyzed by enzymes.
Composition of Enzymes
The composition of enzymes is based on two main components, namely
1. Proteinic Component
2. Non Proteinic Component
1. Proteinic Component
Enzymes are Protein in nature and the proteinic component of enzymes is called Apoenzyme.
2. Non Proteinic Component
Most of the enzymes need a non proteinic component for their activity, which is known as Cofactor. Without Cofactor enzymes cannot show any enzymatic activity. In some enzymes the Cofactor is simply metal ion or organic molecules or ions.
Functions of Enzymes
Enzymes accelerate the rate of reaction as well as drive a reaction to completion, which normally does not occur at room temperature. At the end these are regenerated unchanged. They provide a reaction path way with a lower energy of activation.
Classification of Enzymes
Enzymes are classified into six major classes on the basis of type of reaction it catalyze.
1. Oxido Reductases – Redox Reaction
2. Transferases – Transfer of Group
3. Hydrolases – Hydrolysis Reaction
4. Lyases – Addition Reaction
5. Isomerases – Conversion of Isomers
6. Ligases – Condensation Reaction
Factors Effecting Enzyme Activity
Following are the factors which effect enzyme activity.
1. pH
Every enzyme has its own optimum pH at which it shows maximum activity.
2. Temperature
Every enzyme has its own optimum temperature at which its shows maximum activity. Most of the enzymes show maximum activity between 37ºC – 50ºC.
3. Other Factors
Other factors which effect the enzyme activity are substrate concentration, enzyme concentration and presence of certain ion etc.