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#catalase

8 public questions tagged with this topic.

ZOOLOGY

Which enzyme catalyzes the breakdown of hydrogen peroxide into water and oxygen?

Peroxidase is an enzyme that catalyzes the decomposition of hydrogen peroxide into water and oxygen. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, ph

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Cell Organelles

Which enzyme in peroxisomes detoxifies H₂O₂?

Because peroxisomal oxidases produce stoichiometric hydrogen peroxide during oxidation of fatty acids, urate, D-amino acids and polyamines, cells require robust detoxification to prevent oxidative damage to proteins, lipids and DNA. Catalase is the signature antioxidant enzyme residing in peroxisomal matrix, often forming electron-dense crystalline core visible by electron microscopy in rat liver. It is a 240 kDa heme-containing homotetramer that disproportionates hydrogen peroxide into water and molecular oxygen with extremely high turnover number near ten million molecules per second, one of

Ref: Alberts et al., Molecular Biology of the Cell, 6th ed., Chapter 12: Peroxisomes and Catalase Function.

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Microbial Physiology

Which bacterial enzyme neutralizes hydrogen peroxide?

Reactive oxygen species detoxification crucial for aerobic life. Hydrogen peroxide generated by flavoprotein oxidases and superoxide dismutase dismutation attacks iron sulfur clusters and via Fenton produces hydroxyl radical damaging DNA. Catalase provides efficient removal without reducing equivalents, dismutating two H2O2 to two water and one O2 through heme mediated cycle. Enzyme architecture tetrameric each subunit 60 kDa heme b, NADPH bound protecting against inactivation. Reaction proceeds two steps: oxidation of ferric heme to Compound I oxyferryl porphyrin cation radical by first H2O2,

Ref: Madigan et al., Brock Biology of Microorganisms, Chapter 6: Catalase neutralizes H2O2.

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Microbial Physiology

Which enzyme is crucial for breaking down hydrogen peroxide in aerobic bacteria?

Aerobic respiration inevitably leaks electrons to dioxygen generating superoxide and hydrogen peroxide. H2O2 is particularly hazardous because ferrous iron drives Fenton reaction producing hydroxyl radical that nicks DNA phosphodiester backbone, carbonylates proteins, and peroxidizes lipids. Aerobes counter with catalase, extraordinarily efficient heme tetramer with kcat approaching ten million per second, diffusion limited perfect enzyme. Active site ferriprotoporphyrin IX cycles between ferric resting state and Compound I oxoferryl radical after binding first H2O2, then reduced by second H2O

Ref: Madigan et al., Brock Biology of Microorganisms, 16th ed., Chapter 6: Oxidative stress - Catalase mechanism.

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Microbial Physiology

Which bacterial enzyme neutralizes hydrogen peroxide?

Hydrogen peroxide is unavoidable byproduct of flavoprotein oxidases such as NADH oxidase and autoxidation of menaquinones generating reactive oxygen stress capable of hydroxyl radical formation via Fenton reaction damaging iron-sulfur clusters and DNA. Aerobic bacteria depend on extremely efficient enzymatic detoxification. Catalase is tetrameric heme enzyme containing heme b active site where first H2O2 oxidizes ferric heme to Compound I ferryl oxo porphyrin radical, second H2O2 reduces Compound I releasing water and dioxygen. Catalytic rate is among highest known about ten million molecules

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 12: Catalase Function and Hydrogen Peroxide Neutralization.

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Microbial Physiology

Which enzyme neutralizes hydrogen peroxide (H₂O₂) in bacterial cells?

Hydrogen peroxide at even low micromolar concentrations of 1 to 2 micromolar causes inactivation of mononuclear iron enzymes and iron-sulfur dehydratases such as fumarase via Fenton chemistry generating highly reactive hydroxyl radicals that oxidize DNA generating 8-oxoguanine and protein carbonyls leading to mutagenesis. Bacteria deploy specialized scavenging enzymes for peroxide detoxification. Catalases are predominantly heme-containing tetrameric enzymes containing protoheme IX or heme b in each active site that dismutate two molecules of H2O2 into water and molecular oxygen with extremely

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 12: Catalase and Hydrogen Peroxide Detoxification.

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