What are enzymes inhibitors?

Explanation

The chemicals that can shut off enzyme activity are called inhibitors. They are of 3 types.
1) Competitive inhibitors : Substances which closely resemble the substrate molecules and inhibits the activity of the enzyme are called competitive inhibitors. Eg : Inhibition of succinic dehydrogenase by malonate which closely resembles the substrate succinate.
2) Non-competitive inhibitors : The inhibitors which have no structural similarity with the substrate and bind to an enzyme at locations other than the active sites, so that the globular structure of the enzyme is changed are called non competitive inhibitors. Eg: Metal ions of Copper, Mercury.
3) Feedback inhibitors : The end product of a chain of enzyme catalysed reactions inhibit the enzyme of the first reaction as a part of homoeostatic control of metabolism are called feed back inhibitors. Eg : During respiration (Glycolysis) accumalation of Glucose-6 Phosphate occurs, it inhibits the Hexokinase.