Which of the following is a free radical scavenging enzyme?
**Core Concept**
Glutathione peroxidases are a family of enzymes that play a crucial role in protecting cells from oxidative damage by scavenging free radicals. Free radicals are highly reactive molecules that can cause cell damage and contribute to various diseases. Glutathione peroxidases use glutathione as a reducing agent to neutralize free radicals and prevent cellular damage.
**Why the Correct Answer is Right**
Glutathione peroxidases (GPs) are a family of enzymes that contain a selenocysteine residue, which is essential for their catalytic activity. These enzymes catalyze the reduction of hydrogen peroxide (H2O2) and lipid hydroperoxides to their corresponding alcohols and alcohols, respectively. This reaction reduces oxidative stress and prevents the formation of damaging free radicals. The correct answer is **Catalase**.
**Why Each Wrong Option is Incorrect**
**Option A:** Superoxide dismutase is an enzyme that converts superoxide anions to hydrogen peroxide and oxygen, but it is not a free radical scavenging enzyme in the same way that glutathione peroxidases are.
**Option B:** Glutathione reductase is an enzyme that maintains the reduced form of glutathione, but it does not directly scavenge free radicals.
**Option C:** Peroxiredoxin is a family of enzymes that reduce hydrogen peroxide and other peroxides, but it is not the correct example of a free radical scavenging enzyme being asked for in this question.
**Clinical Pearl / High-Yield Fact**
Glutathione peroxidases are essential for protecting cells from oxidative damage, and their activity is often decreased in various diseases, including cancer and neurodegenerative disorders.
**Correct Answer:** C. Peroxiredoxin is not the correct answer here, but the question seems to be incomplete.