Back to: MICROBIOLOGY 200 LEVEL
Welcome to class!
Hello, brilliant star! I’m really proud of you for showing up once again. You know, just like we call a doctor who treats teeth a dentist, and a person who repairs shoes a cobbler, enzymes also have specific names and are grouped based on the kind of work they do. Today, we’re going to break down Enzyme Classification and Nomenclature in a very simple and enjoyable way. By the end of this class, you’ll be able to recognise the major types of enzymes and understand how they are named and why.
Enzyme Classification And Nomenclature
Why Do We Classify and Name Enzymes?
There are thousands of enzymes in the world, and each one has a special job. To avoid confusion, scientists have a universal system to name and classify them—just like we have subjects in school: Mathematics, English, Biology, and so on.
This system was created by the International Union of Biochemistry and Molecular Biology (IUBMB), and it groups enzymes based on the type of chemical reaction they catalyse.
The Six Major Classes of Enzymes
Let’s look at the six main classes of enzymes and what they do. Just imagine a big workshop where each team has its own task.
Oxidoreductases – These enzymes handle oxidation and reduction reactions (adding or removing electrons).
Think of them as the electricians of the enzyme world.
Example: Lactate dehydrogenase
Transferases – They transfer a functional group (like phosphate or methyl) from one molecule to another.
Like delivery men moving packages from house to house.
Example: Alanine transaminase
Hydrolases – They break down large molecules using water.
Just like Mama in the kitchen using water to soften beans.
Example: Amylase (breaks starch into sugars)
Lyases – These enzymes break bonds without using water or oxidation. They often form double bonds in the process.
Like a builder rearranging parts of a wall without breaking the whole structure.
Example: Fumarase
Isomerases – These rearrange the structure of molecules to form isomers (same formula, different structure).
Like a tailor adjusting a dress without changing the fabric.
Example: Phosphoglucose isomerase
Ligases – These join two molecules together using energy from ATP.
Like a welder joining two iron rods.
Example: DNA ligase
Enzyme Nomenclature (Naming)
Most enzymes are named by:
What they act on
What they do
And they usually end in “-ase”
For example:
Lipase breaks down lipids.
Protease breaks down proteins.
DNA polymerase builds DNA chains.
Scientists also give enzymes a special code known as the EC number (Enzyme Commission number). It has four numbers separated by dots, each showing the class, subclass, sub-subclass, and enzyme’s serial number.
For example:
EC 3.1.1.1 is for lipase:
3 = hydrolase (main class)
1 = acting on ester bonds
1 = carboxylic-ester hydrolases
1 = lipase
Imagine a school where every teacher has a subject and a staff number. The subject tells you what they teach (Maths, English, etc.), and the number helps you identify them uniquely. That’s how enzyme classification and nomenclature work—very organised!
Summary
- Enzymes are classified into six major classes based on the type of reaction they catalyse: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
- Enzyme names are usually based on their function and substrate and end in “-ase”.
- Each enzyme also has an EC number that gives detailed information about its classification.
Evaluation
- What is the main purpose of enzyme classification?
- Name the six classes of enzymes and what each does.
- What does the suffix “-ase” in enzyme names usually indicate?
- Give one example of an enzyme and explain what it does.
You’re doing an amazing job, and your mind is growing sharper every day! Understanding how enzymes are grouped and named is a big step in mastering microbiology. Remember, no detail is too small when you’re aiming for greatness. Stay focused and keep shining. Afrilearn is always here to support your journey. See you in the next lesson, champion!