Biomolecules | NEET | Enzyme - Classification and Nomenclature | Neela Bakore Tutorials

Summary

This script discusses enzyme nomenclature, covering both historical and current naming conventions. It explains older methods like suffixing 'ase' to substrate roots and naming based on the source of the enzyme. The focus then shifts to the systematic International Union of Biochemistry (IUB) classification, which categorizes enzymes into six main groups based on reaction types: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Examples are provided for each group to illustrate their functions in biochemical reactions.

Takeaways

• 🔍 The script discusses the nomenclature of enzymes, which is the system of naming enzymes.
• 🔄 Traditionally, enzymes were named by adding a suffix 'ase' to the root word of their substrate, such as 'malt' becoming 'maltase'.
• 🌿 Another old method of naming involved using the source of the enzyme, like 'bromelain' from pineapples.
• 🔬 A more advanced method involves two-word names, where the first word represents the substrate and the second describes the type of reaction, such as 'pyruvate decarboxylase'.
• 🌐 The most recent method of enzyme nomenclature is provided by the International Union of Biochemistry, which classifies enzymes into six main groups based on the type of reactions they catalyze.
• 🔢 These six groups are numbered as EC1 to EC6, with EC1 being oxidoreductases, EC2 transferases, EC3 hydrolases, EC4 lyases, EC5 isomerases, and EC6 ligases.
• ⚛️ Oxidoreductases (EC1) are involved in oxidation-reduction reactions, such as cytochrome oxidase in the electron transport chain.
• ✂️ Transferases (EC2) facilitate the transfer of functional groups, like the transfer of an amino group in the reaction catalyzed by glutamate pyruvate transaminase.
• 💧 Hydrolases (EC3) break bonds by adding water, which is a common mechanism in digestive enzymes, exemplified by amylase breaking down starch.
• ⚡️ Lyases (EC4) cleave bonds without adding water, such as aldolase breaking down fructose 1,6-bisphosphate into two three-carbon compounds.
• 🔄 Isomerases (EC5) convert one isomer into another, like glucose-6-phosphate isomerizing into fructose-6-phosphate, catalyzed by hexose isomerase.
• 🔗 Ligases (EC6), also known as synthetases, join molecules together, forming new bonds, such as the reaction where pyruvate and carbon dioxide are joined to form oxaloacetate by pyruvate carboxylase.

Q & A

What does nomenclature mean in the context of enzymes?

In the context of enzymes, nomenclature refers to the systematic naming system used to identify and classify enzymes based on their characteristics.

What is the first method mentioned for naming enzymes?

The first method mentioned for naming enzymes involves adding a suffix 'ase' to the root word, which is derived from the substrate on which the enzyme acts.

Can you provide an example of how enzymes were named using the substrate method?

An example of enzyme naming using the substrate method is 'maltase', where 'malt' is the substrate, and 'ase' is added to indicate it's an enzyme.

How are enzymes named based on their source?

Enzymes can be named based on their source by using the name of the organism or substance from which they are derived, such as 'bromelain' from pineapple.

What is the purpose of the two-word naming system for enzymes?

The two-word naming system for enzymes is designed to indicate the substrate and the type of reaction the enzyme catalyzes, providing more specific information about its function.

What does EC stand for in enzyme nomenclature?

EC stands for Enzyme Commission, which is the system used to classify enzymes into six major groups based on the type of reactions they perform.

What are the six major groups of enzymes according to the International Union of Biochemistry?

The six major groups of enzymes are oxidoreductases (EC1), transferases (EC2), hydrolases (EC3), lyases (EC4), isomerases (EC5), and ligases (EC6).

What type of reactions are oxidoreductases involved in?

Oxido-reductases are involved in oxidation and reduction reactions, where they facilitate the transfer of electrons or hydrogen atoms.

Can you give an example of a hydrolase enzyme and its function?

Amylase is an example of a hydrolase enzyme that breaks down starch into smaller sugar molecules by adding water to the glycosidic bonds.

How do ligases differ from other enzymes in terms of their function?

Ligases differ from other enzymes in that they facilitate the joining of molecules to form new compounds, typically by forming new chemical bonds without the addition of water.

What is the significance of the EC number system in enzyme classification?

The EC number system provides a standardized and detailed classification of enzymes based on their catalytic activity, which aids in understanding their functions and relationships.