Enzymes Nomenclature and Classifications | Names and Types | Biochemistry 🧪

Summary

In this video, Medicosis Perfectus explains enzyme classification and nomenclature. It covers the structure of proteins, conjugated proteins, and the role of enzymes as biological catalysts that speed up reactions by lowering activation energy. The video explores six categories of enzymes: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases, explaining their specific functions in biochemical processes. Using analogies and examples like urease and chymotrypsin, the instructor simplifies complex concepts for medical students. The video is part of a larger biochemistry playlist aimed at helping students understand these foundational topics.

Takeaways

• 😀 Enzymes speed up reactions by lowering activation energy without changing the overall free energy or equilibrium of the reaction.
• 🔬 Proteins have primary, secondary, tertiary, and sometimes quaternary structures, and they can combine with prosthetic groups to form conjugated proteins.
• 🛫 Enzymes act like airplanes, helping reactions reach their destination faster but not altering the destination itself.
• 🔄 Enzymes are specific, catalyzing only one reaction or a group of similar reactions, such as urease breaking down urea or chymotrypsin breaking down peptide bonds.
• 💧 Hydrolysis involves breaking down peptide bonds with water, and hydrolytic enzymes like trypsin and chymotrypsin facilitate this process.
• 🔧 Enzymes are classified into six main types: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
• ⚡ Oxidation involves the gain of oxygen or loss of hydrogen or electrons, while reduction is the opposite, involving cofactors like NAD and NADP.
• 🏗️ Transferases move functional groups, such as amino groups in transamination reactions, which require vitamin B6 as a cofactor.
• 💦 Hydrolases break down molecules in the presence of water, such as lipases breaking down lipids or phosphatases removing phosphate groups.
• 🔄 Lyases can either break down molecules without water or bind them together, and isomerases convert molecules into their isomers.

Q & A

What are enzymes and how do they function?

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction. They don't change the overall energy of the reaction or its equilibrium but help the process proceed faster.

How do enzymes affect the activation energy and speed of reactions?

Enzymes lower the activation energy of reactions, which makes the reactions occur faster. However, they do not alter the overall free energy or the final equilibrium position of the reaction.

What are the main categories of enzymes mentioned in the transcript?

The main categories of enzymes discussed are: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Each class has a specific function related to the type of reaction they catalyze.

What are hydrolase enzymes and how do they function?

Hydrolase enzymes break chemical bonds in the presence of water, a process known as hydrolysis. Examples include lipases (which break down fats), peptidases (which break down proteins), and phosphatases (which remove phosphate groups).

What is the difference between a kinase and a phosphatase enzyme?

Kinases are transferase enzymes that add a phosphate group to a molecule, while phosphatases are hydrolase enzymes that remove a phosphate group from a molecule.

What is the role of oxidoreductase enzymes?

Oxidoreductase enzymes catalyze oxidation-reduction (redox) reactions, where the transfer of electrons occurs. Oxidation involves losing electrons, while reduction involves gaining them. Examples include dehydrogenases and reductases.

How do lyase enzymes differ from hydrolase enzymes?

Lyase enzymes break down molecules without the use of water, unlike hydrolases. Lyases can also catalyze reversible reactions, binding or breaking apart molecules in the absence of water.

What is an isomerase enzyme and what does it do?

Isomerase enzymes catalyze the rearrangement of atoms within a molecule, converting it into its isomer. This could involve converting one stereoisomer or constitutional isomer into another.

What is a ligase enzyme and what is its function?

Ligase enzymes catalyze the joining of two molecules by forming a new bond, often requiring ATP. For example, DNA ligase ties together DNA fragments during replication.

What is the difference between synthase and synthetase enzymes?

Synthases catalyze the synthesis of molecules without the need for ATP, while synthetases require ATP to complete the reaction.