Chart of Types of Enzymes and Their Functions with Examples

Enzymes are highly specific, meaning each enzyme typically catalyzes a single type of reaction. Enzymes can be broadly classified into different types based on the nature of the reactions they catalyze. So it is very necessary to know all the types of enzymes and their functions.

Chart of Types of Enzymes and Their Functions

Each class of enzymes plays a specific role, ensuring the smooth execution of metabolic pathways, synthesis of essential biomolecules, and overall maintenance of cellular homeostasis. The types of enzymes and their functions also help to get the basics of enzymes.

If you want to know about Biomolecules, then read this article: 5 Major Biomolecules in Life | Chemical Constituents of Life.

Here is a detailed and easy-to-understand table on the types of enzymes and their functions:

Serial Numbers	Type of Enzyme	Function	Examples	Specific Roles
1.	Oxidoreductases	Catalyze oxidation-reduction reactions, transferring electrons between molecules.	Dehydrogenases: Alcohol dehydrogenase Oxidases: Cytochrome oxidase	Alcohol dehydrogenase: Converts alcohol to aldehyde Cytochrome oxidase: Facilitates electron transfer in the electron transport chain
2.	Transferases	Transfer functional groups (e.g., methyl, glycosyl, phosphate) from one molecule to another.	Kinases: Hexokinase Aminotransferases: Alanine transaminase	Hexokinase: Transfers phosphate groups from ATP to glucose in glycolysis Alanine transaminase: Transfers amino groups in amino acid metabolism
3.	Hydrolases	Catalyze the hydrolysis of various bonds (e.g., ester, glycosidic, peptide) by adding water.	Proteases: Trypsin Lipases: Pancreatic lipase	Trypsin: Breaks down proteins into peptides and amino acids Pancreatic lipase: Hydrolyzes fats into glycerol and fatty acids
4.	Lyases	Catalyze the addition or removal of groups to form double bonds or addition of groups to double bonds.	Decarboxylases: Pyruvate decarboxylase Aldolases: Aldolase	Pyruvate decarboxylase: Removes carboxyl groups in fermentation Aldolase: Splits molecules in glycolysis
5.	Isomerases	Catalyze the rearrangement of atoms within a molecule to form isomers.	Racemases: Alanine racemase Mutases: Phosphoglucomutase	Alanine racemase: Converts one isomer into another in bacterial cell wall synthesis Phosphoglucomutase: Shifts functional groups within a molecule in glucose metabolism
6.	Ligases	Catalyze the joining of two molecules, typically using ATP.	DNA Ligase Acetyl-CoA synthetase	DNA Ligase: Joins DNA fragments during replication and repair Acetyl-CoA synthetase: Forms acetyl-CoA from acetate and coenzyme A in metabolism

Types of Enzymes and Their Functions in Details: Classification of Enzymes

1. Oxidoreductases:

In the types of enzymes and their functions Oxidoreductases are a class of enzymes that play a crucial role in biochemical processes by facilitating oxidation-reduction (redox) reactions. These reactions involve the transfer of electrons from one molecule (the reductant) to another (the oxidant). Oxidoreductases are essential for energy production, metabolism, and detoxification in living organisms.

Other Types of Oxidoreductases

In the types of enzymes and their functions Oxidoreductases can be categorized into several types based on the specific reactions they catalyze and the nature of the donor and acceptor molecules. Here are some key types:

1. Reductases
   • Function: Catalyze the reduction of a substrate by transferring electrons from NADH or NADPH.
   • Examples:
     • Thioredoxin reductase: Involved in maintaining a reduced environment within cells.
     • Ribonucleotide reductase: Converts ribonucleotides to deoxyribonucleotides, essential for DNA synthesis.
2. Peroxidases
   • Function: Reduce hydrogen peroxide by transferring electrons from various substrates.
   • Examples:
     • Catalase: Breaks down hydrogen peroxide into water and oxygen, protecting cells from oxidative damage.
     • Horseradish peroxidase: Used in biochemical assays to detect specific molecules.
3. Hydroxylases
   • Function: Introduce hydroxyl groups into substrates by incorporating oxygen atoms.
   • Examples:
     • Phenylalanine hydroxylase: Converts phenylalanine to tyrosine, a precursor for neurotransmitters.
     • Prolyl hydroxylase: Modifies proline residues in collagen, essential for its stability.

2. Transferases

In the types of enzymes and their functions Transferases are a class of enzymes that play a vital role in various biochemical processes by facilitating the transfer of functional groups from one molecule to another. These enzymes are crucial for numerous metabolic pathways, including those involved in energy production, biosynthesis, and signal transduction.

Types of Transferases

Transferases can be categorized into several types based on the specific functional groups they transfer.

1. Methyltransferases
   • Function: Transfer methyl groups from donor molecules such as S-adenosylmethionine to acceptor molecules, involved in gene regulation and other processes.
   • Examples:
     • DNA methyltransferase: Methylates DNA, influencing gene expression and epigenetic regulation.
     • Histone methyltransferase: Methylates histones, affecting chromatin structure and gene expression.
2. Glycosyltransferases
   • Function: Transfer glycosyl groups to acceptor molecules, crucial for the synthesis of glycoproteins, glycolipids, and polysaccharides.
   • Examples:
     • Glycogen synthase: Transfers glucose from UDP-glucose to glycogen, essential for glycogen synthesis.
     • Oligosaccharyltransferase: Transfers oligosaccharides to nascent proteins during glycosylation in the endoplasmic reticulum.
3. Acyltransferases
   • Function: Transfer acyl groups from acyl-CoA to acceptor molecules, involved in lipid metabolism and synthesis.
   • Examples:
     • Acetyl-CoA carboxylase: Catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, a key step in fatty acid synthesis.
     • Lecithin-cholesterol acyltransferase (LCAT): Transfers acyl groups to cholesterol, forming cholesteryl esters in lipid metabolism.

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3. Hydrolases

In the types of enzymes and their functions Hydrolases are a class of enzymes that catalyze the hydrolysis of chemical bonds. They play a crucial role in various biological processes by breaking down complex molecules into simpler ones, facilitating metabolism, digestion, and other essential functions in living organisms. Hydrolases are highly diverse and specific, each tailored to act on particular substrates.

Types of Hydrolases

Hydrolases are classified based on the type of bond they act upon:

1. Esterases: These enzymes hydrolyze ester bonds, which are common in lipids. An example is lipase, which breaks down fats into fatty acids and glycerol.
2. Glycosidases: Also known as glycoside hydrolases, these enzymes break glycosidic bonds in carbohydrates. Amylase, which converts starch into sugars, is a well-known glycosidase.
3. Peptidases (Proteases): These enzymes hydrolyze peptide bonds in proteins. Trypsin and chymotrypsin, which are involved in protein digestion, are examples of peptidases.
4. Nucleases: These enzymes cleave the phosphodiester bonds in nucleic acids. DNase and RNase are nucleases that degrade DNA and RNA, respectively.
5. Phosphatases: These enzymes remove phosphate groups from molecules. Alkaline phosphatase is a key enzyme involved in dephosphorylation.

Industrial and Medical Applications

Hydrolases have significant industrial and medical applications:

1. Biotechnology: Hydrolases are used in recombinant DNA technology to manipulate genetic material. Restriction enzymes, a type of nuclease, cut DNA at specific sequences, enabling genetic engineering.
2. Food Industry: Enzymes like pectinase and cellulase are used in food processing to enhance texture, clarity, and shelf-life. Lactase is added to dairy products to make them lactose-free.
3. Medicine: Hydrolase inhibitors are used as drugs to treat diseases. For example, protease inhibitors are crucial in managing HIV infection. Enzyme replacement therapy, involving enzymes like alpha-galactosidase, treats metabolic disorders such as Fabry disease.
4. Environmental Applications: Hydrolases are employed in bioremediation to degrade pollutants. Lipases, for instance, can break down oil spills, making them valuable in environmental cleanup.

4. Lyases

In the types of enzymes and their functions Lyases are a class of enzymes that play crucial roles in various biochemical processes by catalyzing the addition or removal of groups to form double bonds or the breaking of bonds without hydrolysis or oxidation. These enzymes are essential for a range of metabolic pathways, including those involved in energy production, biosynthesis, and cellular signaling.

Types of Lyases

Lyases can be categorized into several types based on the specific reactions they catalyze. Here are some key types:

1. Dehydrases
   • Function: Catalyze the removal of water from a substrate, often forming a double bond.
   • Examples:
     • Enolase: Converts 2-phosphoglycerate to phosphoenolpyruvate in glycolysis by removing water.
     • Fumarase: Converts fumarate to malate by adding water in the citric acid cycle.
2. Synthases
   • Function: Catalyze the addition of groups to double bonds, often forming new compounds.
   • Examples:
     • Citrate synthase: Combines acetyl-CoA and oxaloacetate to form citrate in the citric acid cycle.
     • ATP citrate lyase: Converts citrate to acetyl-CoA and oxaloacetate in fatty acid biosynthesis.
3. Lyases Involved in Ring Formation
   • Function: Catalyze the formation or breakage of rings in organic molecules.
   • Examples:
     • Adenylosuccinate lyase: Cleaves adenylosuccinate to form fumarate and AMP in the purine nucleotide cycle.
     • Histidine ammonia-lyase: Converts histidine to urocanate in histidine catabolism by removing ammonia.

5. Isomerases

In the types of enzymes and their functions Isomerases are a class of enzymes that catalyze the rearrangement of atoms within a molecule, transforming it into an isomer. This process involves changing the structure of a molecule without adding or removing elements, allowing the molecule to adopt a different configuration. Isomerases play a crucial role in various biochemical pathways, ensuring the proper functioning of metabolic processes.

Types of Isomerases

Isomerases are categorized based on the type of isomerization they facilitate:

1. Cis-Trans Isomerases: These enzymes facilitate the conversion between cis and trans forms of molecules. An example is peptidyl-prolyl cis-trans isomerase, which helps in protein folding by converting proline residues from cis to trans configurations.
2. Intramolecular Lyases: These enzymes catalyze the breaking and forming of bonds within a molecule to create isomers. An example is aconitase, which converts citrate to isocitrate in the citric acid cycle.

Mechanism of Action

Isomerases function by stabilizing the transition state of the substrate, lowering the activation energy required for the isomerization reaction. This often involves conformational changes in the enzyme to accommodate the substrate and facilitate the rearrangement of atoms.

For instance, in the case of phosphoglucomutase, the enzyme binds glucose-1-phosphate and transfers a phosphate group from the enzyme to the substrate, forming a glucose-1,6-bisphosphate intermediate. This intermediate is then converted to glucose-6-phosphate, completing the isomerization.

Industrial and Medical Applications

Isomerases have significant industrial and medical applications:

1. Biotechnology: Isomerases are used in the synthesis of pharmaceuticals, agrochemicals, and fine chemicals. Their ability to produce specific isomers with high precision makes them valuable in creating compounds with desired biological activity.
2. Medical Diagnostics and Treatment: Enzyme assays involving isomerases help diagnose metabolic disorders. For example, glucose-6-phosphate dehydrogenase (G6PD) deficiency is diagnosed by measuring the activity of G6PD, an enzyme involved in the pentose phosphate pathway.
3. Drug Development: Isomerase inhibitors are used as therapeutic agents. Topoisomerase inhibitors, for example, are used in cancer treatment to prevent DNA replication in rapidly dividing cancer cells.
4. Food Industry: Isomerases like glucose isomerase are used to convert glucose to fructose in the production of high-fructose corn syrup, a common sweetener in the food industry.

6. Ligases

In the types of enzymes and their functions Ligases are a class of enzymes that play a critical role in various biochemical processes by catalyzing the joining of two molecules. This reaction often involves the formation of a new chemical bond with the concomitant hydrolysis of a high-energy molecule such as ATP. Ligases are essential for a variety of biological functions, including DNA replication, repair, and metabolic pathways. This article provides a detailed overview of ligase enzymes, their functions, and their significance in biological systems.

Types of Ligases

Ligases can be categorized into several types based on the specific reactions they catalyze. Here are some key types:

1. RNA Ligases
   • Function: Catalyze the joining of RNA strands, playing a role in RNA repair and processing.
   • Examples:
     • RNA Ligase (Rnl1): Joins RNA molecules during RNA splicing and repair in viruses and some bacteria.
     • T4 RNA Ligase: Used in laboratory techniques for ligating single-stranded RNA molecules.
2. Aminoacyl-tRNA Synthetases
   • Function: Catalyze the attachment of amino acids to their corresponding tRNA molecules, a crucial step in protein synthesis.
   • Examples:
     • Isoleucyl-tRNA Synthetase: Attaches isoleucine to its tRNA.
     • Phenylalanyl-tRNA Synthetase: Attaches phenylalanine to its tRNA.
3. Peptide Synthases
   • Function: Catalyze the formation of peptide bonds between amino acids during non-ribosomal peptide synthesis.
   • Examples:
     • Gramicidin S Synthetase: Involved in the synthesis of the antibiotic gramicidin S.
     • Tyrocidine Synthetase: Synthesizes tyrocidine, another antibiotic.
4. Other Ligases
   • Function: Catalyze a variety of bond-forming reactions involving different substrates.
   • Examples:
     • Glutathione Synthetase: Forms glutathione from glutamate, cysteine, and glycine, important for cellular antioxidant defense.
     • Acetyl-CoA Synthetase: Converts acetate into acetyl-CoA, a key intermediate in metabolism.

Understanding the types of enzymes and their functions provides insights into how cells function and opens avenues for developing treatments for various diseases and improving industrial processes.

FAQ on Types of Enzymes and Their Functions