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What are Proteins, their Types & Structures?May 9, 2020
What are Enzymes
Enzymes are biological molecules (characteristically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place inside cells.
They are dynamic for life and serve a wide range of vital functions in the body, such as aiding in digestion and metabolism.
They support speed up chemical reactions in the human body. They bind to molecules and alter them in particular ways. They are necessary for respiration, digesting food, muscle and nerve function, among thousands of other roles.
What are important Types and Functions
The biochemical reactions occurring in the body are mainly of 6 types
- Oxidoreductases: They pass oxidation and reduction reactions and hence are called oxidoreductases. In these reactions, electrons in the form of hydride ions or hydrogen atoms are transmitted. When a substance is being oxidized, these enzymes act as the hydrogen donor. These enzymes are called dehydrogenases or reductases. When the oxygen atom is the receiver, these enzymes are called oxidases.
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- Transferases: These enzymes are responsible for relocating functional groups from one molecule to another. Example: alanine aminotransferase which scuffles the alpha‐amino group between alanine and aspartate etc. Some transferases also transfer phosphate groups between ATP and other compounds, sugar remains to form disaccharides such as hexokinase in glycolysis.
- Ligases: These enzymes do a function that is opposite to that of the hydrolases. Where hydrolases break bonds by adding water, ligases make bonds by removal of the water component. There are different subdivisions of ligases which involve the synthesis of ATP.
- Hydrolases: These enzymes catalyze reactions that include the process of hydrolysis. They disrupt single bonds by adding water. Some hydrolases function as digestive enzymes because they disrupt the peptide bonds in proteins. Hydrolases can also be a type of transferases as they transfer the water molecule from one compound to another. Example: Glucose-6-phosphatase that eliminates the phosphate group from glucose-6-phosphate, leaving glucose and H3PO4.
- Lyases: These enzymes catalyze reactions where functional groups are added to break double bonds in molecules or where double bonds are made by the removal of functional groups. Example: Pyruvate decarboxylase is a lyase that removes CO2 from pyruvate. Other examples are deaminases and dehydratases.
- Isomerases: These enzymes catalyze the reactions where a functional group is transferred to another position within the same molecule such that the resulting molecule is essentially an isomer of the earlier molecule. Example: triosephosphate isomerase and phosphoglucose isomerase for converting glucose 6-phosphate to fructose 6-phosphate.