An essential component of glutathione peroxidase is?

Appeared in: DSSSB - 29 August 2019 (Shift-1)

Explanation

Glutathione peroxidase is a key antioxidant enzyme that requires selenium as an essential structural and functional component.
Selenium is incorporated into the enzyme's active site in the form of the amino acid selenocysteine, which is crucial for its catalytic activity.
The primary function of this selenoenzyme is to protect cells from oxidative damage by neutralizing harmful reactive oxygen species like hydrogen peroxide.

Option B: Zinc is not a component of glutathione peroxidase. It is an essential cofactor for a different antioxidant enzyme.
Option C: Manganese is not a component of glutathione peroxidase. It is the specific cofactor for the mitochondrial version of another antioxidant enzyme.
Option D: Copper is not a component of glutathione peroxidase. It works with zinc in a different antioxidant enzyme.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Role of trace elements in antioxidant enzymes as background academic context rather than a clinical decision trigger.
Nurses should recognize that selenium deficiency impairs the body's defense against oxidative stress, which can contribute to conditions like Keshan disease (a form of cardiomyopathy) and muscle degeneration.
Monitoring the nutritional status of patients on long-term total parenteral nutrition (TPN) is crucial, as they are at risk for various trace element deficiencies, including selenium.
What if? If a patient has symptoms of both selenium and iodine deficiency, it's vital to address both. Selenium is required for deiodinase enzymes, which convert the thyroid hormone T4 to its active form, T3. Selenium deficiency can therefore worsen the clinical manifestations of iodine deficiency, such as goiter and cretinism.

How to Approach the Question

This is a factual recall question based on biochemistry.
First, identify the key terms in the question: the enzyme 'glutathione peroxidase' and the phrase 'essential component'.
The question asks to identify the specific mineral that is a necessary part of this enzyme.
Access your knowledge about major antioxidant enzymes and their required mineral cofactors.
Recall or deduce that glutathione peroxidase is a selenoenzyme, meaning it depends on selenium.
Differentiate this from other antioxidant enzymes: Superoxide Dismutase (uses Copper, Zinc, Manganese) and Catalase (uses Iron).

Concept Tested & Keywords

Q3_2SISL_eXxreywNMeahV

E6 Medicine Harrison 22e Part 2 p. 519-521

E6 Harper's Illustrated Biochemistry2023 (pp 26-793 of 813) p. 86-88

Practise the full DSSSB - 29 August 2019 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.