Skip to content
Login Register

#bacterial enzyme

3 public questions tagged with this topic.

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.

View Details
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.

View Details
Microbial Physiology

Which bacterial enzyme is involved in hydrolyzing organic phosphate esters during phosphate starvation?

Phosphate is often limiting nutrient in natural environments such as soils, freshwater lakes and host tissues, triggering broad starvation response orchestrated by Pho regulon controlled by two-component sensor kinase response regulator PhoR-PhoB. Under phosphate starvation where intracellular orthophosphate falls below micromolar threshold, bacteria induce high-affinity scavenging enzymes to liberate inorganic phosphate from organic sources. Alkaline phosphatase encoded by phoA in Escherichia coli is a periplasmic nonspecific phosphomonoesterase that hydrolyzes phosphoester bonds in diverse s

Ref: Madigan et al., Brock Biology of Microorganisms, 16th ed., Chapter 7: Pho Regulon and Alkaline Phosphatase Function.

View Details