Difference between competitive inhibition and non-competitive inhibition

Competitive Inhibition

1. The structure of inhibition molecule is similar to that of the substrate.

2. The inhibitors get attached to the active site of the enzyme.

3. It competes with the substrate molecule or for the enzyme.

4. It does not alter the structure of the enzyme.

5. The reaction can be reversed by increasing the substrate concentration.

6. Example: Sulpha drugs given to bacteria, complete with para-amino benzoic acid (PABA) and folic acid synthesis is Inhibited.

Non-competitive inhibition

1. The Structure of the inhibitor molecule is entirely different.

2. The inhibitor forms complex at a point other than the active site.

3. It does not complete with the substrate.

4. It alters the structure of the enzyme in such a way that the substrate may get attached to the active site but products are not formed.

5. The reaction goes on decreasing as more and more inhibitors contact the enzyme till saturation is reached.

6. Example: Cyanide combines with the prosthetic group of cytochromo oxidase and inhibits the election transport chain.