Podcast
Questions and Answers
Which coenzymes are involved in the generation of ATP from the oxidation of fuels?
Which coenzymes are involved in the generation of ATP from the oxidation of fuels?
- NADH and NADPH
- Vitamin E and vitamin C
- NAD+ and flavin adenine dinucleotide (FAD) (correct)
- Coenzyme A and phosphopantetheine
Which compounds act as antioxidants and protect against oxygen free-radical injury?
Which compounds act as antioxidants and protect against oxygen free-radical injury?
- NAD+ and flavin adenine dinucleotide (FAD)
- Vitamin E and vitamin C (ascorbic acid) (correct)
- Coenzyme A and phosphopantetheine
- NADH and NADPH
Which category of enzymes is involved in the transfer of hydrogen from the substrate to an electron-accepting coenzyme?
Which category of enzymes is involved in the transfer of hydrogen from the substrate to an electron-accepting coenzyme?
- Oxidoreductases
- Hydrolases
- Transferases
- Dehydrogenases (correct)
Which coenzymes work with metals to transfer single electrons to oxygen?
Which coenzymes work with metals to transfer single electrons to oxygen?
Which coenzyme is covalently attached to a lysine residue in the carboxylase enzyme for carboxylation reactions?
Which coenzyme is covalently attached to a lysine residue in the carboxylase enzyme for carboxylation reactions?
Which coenzyme has a reactive aldehyde that forms a covalent intermediate with amino acids, acting as an electron-withdrawing group for electrophilic catalysis?
Which coenzyme has a reactive aldehyde that forms a covalent intermediate with amino acids, acting as an electron-withdrawing group for electrophilic catalysis?
Which coenzymes have unique functional groups for electron transfer and require enzyme participation?
Which coenzymes have unique functional groups for electron transfer and require enzyme participation?
In oxidation reactions, which coenzyme accepts a hydride ion from lactate, leading to the reduction of NADH?
In oxidation reactions, which coenzyme accepts a hydride ion from lactate, leading to the reduction of NADH?
How is NAD+ synthesized?
How is NAD+ synthesized?
Which metal ion is involved in the oxidation of ethanol to acetaldehyde by alcohol dehydrogenase (ADH) in the liver?
Which metal ion is involved in the oxidation of ethanol to acetaldehyde by alcohol dehydrogenase (ADH) in the liver?
What role do metal ions like Mg2+ play in catalysis?
What role do metal ions like Mg2+ play in catalysis?
How is ethanol in serum analyzed?
How is ethanol in serum analyzed?
What role do metal ions play in enzymes like alcohol dehydrogenase?
What role do metal ions play in enzymes like alcohol dehydrogenase?
Apart from catalytic roles, what other function can cofactors play in enzymes?
Apart from catalytic roles, what other function can cofactors play in enzymes?
Which type of enzyme catalyzes the cleavage of carbon–carbon bond, such as fructose 1,6-bisphosphate aldolase in glycolysis?
Which type of enzyme catalyzes the cleavage of carbon–carbon bond, such as fructose 1,6-bisphosphate aldolase in glycolysis?
What type of enzyme removes water from carbon–carbon bonds to form a double bond?
What type of enzyme removes water from carbon–carbon bonds to form a double bond?
Which enzyme type creates isomers of the starting material by rearranging the existing atoms of a molecule?
Which enzyme type creates isomers of the starting material by rearranging the existing atoms of a molecule?
What type of enzyme synthesizes C–C, C–S, C–O, and C–N bonds in reactions coupled to the cleavage of a high-energy phosphate bond in ATP or another nucleotide?
What type of enzyme synthesizes C–C, C–S, C–O, and C–N bonds in reactions coupled to the cleavage of a high-energy phosphate bond in ATP or another nucleotide?
Which enzyme type cleaves C–O, C–N, or C–S bonds through hydrolysis reactions?
Which enzyme type cleaves C–O, C–N, or C–S bonds through hydrolysis reactions?
What type of enzyme catalyzes carbon–carbon bond cleavage by means other than hydrolysis or oxidation?
What type of enzyme catalyzes carbon–carbon bond cleavage by means other than hydrolysis or oxidation?
Which enzyme type catalyzes the transfer of a group that exists as a good leaving group on the donor molecule?
Which enzyme type catalyzes the transfer of a group that exists as a good leaving group on the donor molecule?
What type of enzyme is involved in the donation of a nitrogen group from an amino acid to an α-keto acid, forming a new amino acid and the corresponding donor α-keto acid?
What type of enzyme is involved in the donation of a nitrogen group from an amino acid to an α-keto acid, forming a new amino acid and the corresponding donor α-keto acid?
Which enzyme type requires the coenzyme pyridoxal phosphate?
Which enzyme type requires the coenzyme pyridoxal phosphate?
What type of enzyme may be called synthases when the physiologically important aspect is the compound synthesized?
What type of enzyme may be called synthases when the physiologically important aspect is the compound synthesized?
How do enzymes accelerate reaction rates?
How do enzymes accelerate reaction rates?
What is the mechanism of action of penicillin as an enzyme inhibitor?
What is the mechanism of action of penicillin as an enzyme inhibitor?
How does allopurinol function as an inhibitor?
How does allopurinol function as an inhibitor?
What is the consequence of mercury binding to reactive sulfhydryl groups in enzyme active sites?
What is the consequence of mercury binding to reactive sulfhydryl groups in enzyme active sites?
How does lead contribute to toxicity?
How does lead contribute to toxicity?
What is the primary effect of ethanol oxidation in the liver?
What is the primary effect of ethanol oxidation in the liver?
What is the role of xanthine oxidase in purine metabolism?
What is the role of xanthine oxidase in purine metabolism?
How does acetylcholine accumulation affect the autonomic nervous system?
How does acetylcholine accumulation affect the autonomic nervous system?
What type of reactions do transferases catalyze?
What type of reactions do transferases catalyze?
How does heavy-metal toxicity occur?
How does heavy-metal toxicity occur?
What is the consequence of allopurinol's inhibition of xanthine oxidase?
What is the consequence of allopurinol's inhibition of xanthine oxidase?
How does ethanol oxidation in the liver contribute to tissue damage?
How does ethanol oxidation in the liver contribute to tissue damage?
Study Notes
Enzyme Inhibitors and Toxicity
- Acetylcholine accumulation overstimulates the autonomic nervous system, causing vomiting, cramps, salivation, and sweating.
- Penicillin is a transition-state analog that binds tightly to glycopeptidyl transferase, inhibiting bacterial cell wall synthesis.
- Penicillin is a suicide inhibitor that irreversibly binds to the enzyme's active site, inactivating it.
- Allopurinol is a suicide inhibitor of xanthine oxidase, decreasing urate production and treating gout.
- Heavy-metal toxicity occurs when metals like mercury, lead, aluminum, or iron bind tightly to enzyme functional groups.
- Mercury binds to reactive sulfhydryl groups in enzyme active sites, causing toxicity.
- Lead replaces normal functional metals in enzymes, such as calcium, iron, or zinc, causing developmental and neurologic toxicity.
- Xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and uric acid, and is inhibited by allopurinol.
- Allopurinol prevents the generation of uric acid, treating gout by inhibiting xanthine oxidase.
- Ethanol oxidation in the liver produces acetaldehyde, which can damage the liver, heart, and other tissues.
- At low ethanol intakes, acetaldehyde is safely oxidized to acetate in the liver by aldehyde dehydrogenases.
- Transferases catalyze group transfer reactions, such as the transfer of high-energy phosphates, carbohydrates, or fatty acyl groups.
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Description
Test your knowledge of enzyme inhibitors and toxicity with this quiz. Explore the effects of acetylcholine accumulation, penicillin as a transition-state analog, allopurinol as a suicide inhibitor, and the impact of heavy-metal toxicity. Learn about the inhibition of xanthine oxidase by allopurinol and ethanol oxidation in the liver.
