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Questions and Answers
What type of enzyme catalyzes the formation of isomers by rearranging the existing atoms in a molecule?
What type of enzyme catalyzes the formation of isomers by rearranging the existing atoms in a molecule?
- Isomerase (correct)
- Synthetase
- Mutase
- Ligase
Which enzyme catalyzes the conversion of citrate into isocitrate?
Which enzyme catalyzes the conversion of citrate into isocitrate?
- Citrate synthase
- Isomerase (correct)
- Glutamine synthetase
- y-Glutamylcysteine synthetase
Which of the following enzymes requires ATP to catalyze the joining of two substrates?
Which of the following enzymes requires ATP to catalyze the joining of two substrates?
- Synthetase (correct)
- Mutase
- Ligase (correct)
- Isomerase
What type of reaction do mutases catalyze?
What type of reaction do mutases catalyze?
Which enzyme is responsible for the conversion of L-glutamate to L-glutamine?
Which enzyme is responsible for the conversion of L-glutamate to L-glutamine?
Which enzyme class is responsible for the transfer of functional groups?
Which enzyme class is responsible for the transfer of functional groups?
What type of reaction do hydrolases primarily perform?
What type of reaction do hydrolases primarily perform?
Which of the following enzymes catalyzes oxidation-reduction reactions?
Which of the following enzymes catalyzes oxidation-reduction reactions?
Which enzyme class performs ATP-dependent condensations?
Which enzyme class performs ATP-dependent condensations?
In which class would you categorize dehydrogenases?
In which class would you categorize dehydrogenases?
What do oxygenases do in biochemical reactions?
What do oxygenases do in biochemical reactions?
Which enzyme class does not involve the transfer of electrons?
Which enzyme class does not involve the transfer of electrons?
What action is associated with the class of enzymes known as ligases?
What action is associated with the class of enzymes known as ligases?
What does the suffix '-ase' typically signify when naming enzymes?
What does the suffix '-ase' typically signify when naming enzymes?
Which of the following is an example of an enzyme classified as an oxidoreductase?
Which of the following is an example of an enzyme classified as an oxidoreductase?
What is the primary function of enzymes classified under EC 2?
What is the primary function of enzymes classified under EC 2?
In the EC classification system, what does the first element of the code signify?
In the EC classification system, what does the first element of the code signify?
Which class of enzymes is primarily involved in the process of hydrolysis?
Which class of enzymes is primarily involved in the process of hydrolysis?
What type of reaction do lyases (EC 4) typically catalyze?
What type of reaction do lyases (EC 4) typically catalyze?
What do the four elements in the Enzyme Commission number represent?
What do the four elements in the Enzyme Commission number represent?
Which enzyme classification would 'Lactate dehydrogenase' belong to?
Which enzyme classification would 'Lactate dehydrogenase' belong to?
What type of enzyme is aspartate aminotransferase (AST)?
What type of enzyme is aspartate aminotransferase (AST)?
Which of the following enzymes is a hydrolase that cleaves peptide bonds in proteins?
Which of the following enzymes is a hydrolase that cleaves peptide bonds in proteins?
What reaction is catalyzed by the enzyme pyrophosphatase?
What reaction is catalyzed by the enzyme pyrophosphatase?
Which of the following statements is true about lyases?
Which of the following statements is true about lyases?
Which enzyme is specifically known for catalyzing the formation of a carbon-carbon bond?
Which enzyme is specifically known for catalyzing the formation of a carbon-carbon bond?
What type of bonds do proteases primarily cleave?
What type of bonds do proteases primarily cleave?
Which of the following best describes the function of aldolases?
Which of the following best describes the function of aldolases?
Which enzyme is involved in the hydrolysis of starch?
Which enzyme is involved in the hydrolysis of starch?
What type of reaction do transferases catalyze?
What type of reaction do transferases catalyze?
Which enzyme is specifically mentioned as catalyzing the conversion of xanthine to uric acid?
Which enzyme is specifically mentioned as catalyzing the conversion of xanthine to uric acid?
What is required by all transaminases for their catalytic function?
What is required by all transaminases for their catalytic function?
Which chemical compound is produced along with H2O2 when xanthine is converted by xanthine oxidase?
Which chemical compound is produced along with H2O2 when xanthine is converted by xanthine oxidase?
What happens to alanine aminotransferase (ALT) levels in the blood following liver damage?
What happens to alanine aminotransferase (ALT) levels in the blood following liver damage?
Which of the following statements about transfer reactions is true?
Which of the following statements about transfer reactions is true?
Which of the following is not a type of transferase mentioned?
Which of the following is not a type of transferase mentioned?
What is the primary function of the enzyme xanthine oxidase?
What is the primary function of the enzyme xanthine oxidase?
Flashcards
Isomerases
Isomerases
Enzymes that catalyze the rearrangement of atoms within a molecule, creating isomers.
Mutases
Mutases
Enzymes that catalyze the transfer of a functional group, such as a phosphate group, from one molecule to another.
Ligases
Ligases
Enzymes that catalyze the joining of two molecules, often requiring the input of energy from ATP.
Enolase
Enolase
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Citrate Synthase
Citrate Synthase
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Transferase
Transferase
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Kinase
Kinase
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Glycosyltransferase
Glycosyltransferase
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Acyltransferase
Acyltransferase
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Transamination
Transamination
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Transaminases or Aminotransferases
Transaminases or Aminotransferases
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Pyridoxal Phosphate
Pyridoxal Phosphate
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Alanine Aminotransferase (ALT) or Glutamate Pyruvate Transaminase (GPT)
Alanine Aminotransferase (ALT) or Glutamate Pyruvate Transaminase (GPT)
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What enzyme transfers a phosphate group from ATP to glucose's 6th carbon?
What enzyme transfers a phosphate group from ATP to glucose's 6th carbon?
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What are oxidoreductases?
What are oxidoreductases?
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What are dehydrogenases?
What are dehydrogenases?
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What is NAD+?
What is NAD+?
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What are transferases?
What are transferases?
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What are kinases?
What are kinases?
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What are hydrolases?
What are hydrolases?
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What are lyases?
What are lyases?
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Hydrolases
Hydrolases
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Proteases
Proteases
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Decarboxylases
Decarboxylases
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Dehydratases
Dehydratases
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Synthases
Synthases
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Thiolases
Thiolases
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Aldolase
Aldolase
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Early Enzyme Naming
Early Enzyme Naming
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The '-ase' Rule
The '-ase' Rule
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Double Duty Names
Double Duty Names
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Enzyme Classification
Enzyme Classification
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EC Number
EC Number
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EC Number: Class
EC Number: Class
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EC Number: Subclasses
EC Number: Subclasses
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EC Number: Specific Enzyme or Substrate
EC Number: Specific Enzyme or Substrate
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Study Notes
Enzyme Naming
- Early enzyme names were arbitrary, given by discoverers, e.g., pepsin, trypsin, chymotrypsin.
- These names didn't convey information about the enzyme's function or substrate.
- A suffix "-ase" was commonly added to the substrate name, e.g., lipase acts on lipids, nuclease on nucleic acids.
- Alternatively, names describe enzyme function, e.g., oxidases, decarboxylases, dehydrogenases.
- Some names describe both substrate and function, e.g., lactate dehydrogenase oxidizes lactate.
Enzyme Classification
- In 1961, the Enzyme Commission (EC) under the International Union of Pure and Applied Chemistry (IUPAC) introduced a system for classifying enzymes.
- Enzymes are grouped into six major classes based on the reaction they catalyze.
- Each class is further divided into subclasses, sub-subclasses, and specific subclasses, giving a unique four-part code for each enzyme (e.g., EC (0.0.0.0)).
- The code uses four numbers separated by periods. The first number indicates the class; the second and third the subclass and sub-subclass; the fourth the specific enzyme within that sub-subclass.
Enzyme Classes
- EC 1. Oxidoreductases: These enzymes catalyze oxidation-reduction reactions. In these reactions, one substrate gains electrons (reduction) while another loses electrons (oxidation).
- Examples include dehydrogenases, oxidases, and peroxidases. Often involve transfer of hydride (H-) ions or hydrogen atoms. Electron transfer often uses coenzymes like NAD+ /NADH as electron acceptors.
- EC 2. Transferases: These enzymes move a functional group from one molecule to another. If the transferred group is a high-energy phosphate, the enzyme is a kinase. If it is a carbohydrate residue, it's a glycosyltransferase; If it is a fatty acyl group, it is an acyltransferase.
- EC 3. Hydrolases: These enzymes catalyze the hydrolysis of a chemical bond. They cleave bonds using water, breaking a substrate.
- Examples include amidases, phosphatases, peptidases (protein-digesting), proteases (cleave peptide bonds), lipases (for lipid hydrolysis), amylases (for carbohydrate hydrolysis).
- EC 4. Lyases: These enzymes cleave C-C, C-O, or C-N bonds without water or oxidation. They typically form double bonds.
- Examples include aldolases, dehydrogenases, and synthases.
- EC 5. Isomerases: These enzymes rearrange the atoms within a molecule to form an isomer, a molecule with the same chemical formula but a different structure.
- Examples include mutases.
- EC 6. Ligases (Synthetases): These enzymes join two substrates together. These reactions require energy from ATP or a similar source.
- Examples include carboxylases.
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Description
This quiz explores the fundamental principles behind enzyme naming and classification as established by the Enzyme Commission. Understand how enzymes are categorized based on their function and the historical context of their naming conventions. Test your knowledge of the various classes and subclassifications of enzymes.
