Introduction to Enzymes.

 What are enzymes?

Enzymes are catalysts that is they speed up the rates of reactions without undergoing any sort of permanent change. They are also called as "Biocatalysts". The word "enzyme" is derived from the Greek language and its literal meaning is "in yeast" and it was first used by scientist Khune in 1878. The term enzyme was thus intended to emphasize that catalytic activity was "in yeast" that is a manifestation of an extraction or a secretion rather than of the whole organism.

History of study on Enzymes.

1. In 1897, scientist Buchner did an experiment to show that activity of an enzyme could be expressed without the need of intact cellular structure by using filtrates of yeast extracts to catalyse the fermentation process.

2. In 1894, Emil Fischer performed some classical studies on carbohydrate metabolizing enzymes in which he demonstrated the specificity shown by an enzyme for a substrate. On the basis of his experiments he proposed the famous "lock and key" hypothesis to describe this interactions.

3. In 1926, Sumner was the first to crystallize an enzyme named urease which catalyses the hydrolysis of urea to yield carbon dioxide and ammonia.

4. In 1958, Koshland proposed the "induce fit" theory to account for the cataytic power and specificity shown by enzymes.

5. Scientist Monod, put forward "allosteric model" of enzymes to explain how the activity of certain enzymes can be regulated by the binding of small molecules known as "effectors" quantitatively.

6. The first chemical synthesis of an enzyme named "ribonuclease" from an amino acid precursor was reported in 1969.

7. In 1986, Cech discovered that the RNA can also act as a catalyst for reactions involving hydrolysis of RNA.