The mineral which functions as a prosthetic group in enzymes is?

DSSSB - 29 August 2019 (Shift-2)

Biochemistry & Nutrition

Easy

Appeared in: DSSSB - 29 August 2019 (Shift-2)

Explanation

A prosthetic group is a non-protein component, such as a metal ion, that is tightly and permanently bound to an enzyme and is essential for its activity.
Copper is an essential trace mineral that functions as a prosthetic group for several critical enzymes involved in energy production, antioxidant defense, connective tissue formation, and pigmentation.
Examples of copper-containing enzymes include cytochrome c oxidase (for cellular respiration) and lysyl oxidase (for collagen synthesis).
The tight binding of copper distinguishes its role as a prosthetic group from other cofactors that bind more loosely.

Option A: Lithium is not a naturally occurring prosthetic group in human enzymes. Its primary relevance is as a medication for psychiatric conditions like bipolar disorder.
Option B: Potassium is a major intracellular electrolyte. While it can act as a cofactor that activates some enzymes, it binds loosely and reversibly, so it is not classified as a prosthetic group.
Option C: Sodium is the primary extracellular electrolyte. Like potassium, it is crucial for fluid balance and nerve impulses but does not serve as a tightly bound prosthetic group for enzymes.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Role of minerals as enzyme prosthetic groups as background academic context rather than a clinical decision trigger.
Understanding the role of copper is crucial for recognizing disorders of its metabolism. Wilson's disease is a genetic disorder causing copper overload, leading to severe liver and brain damage.
Conversely, copper deficiency, though rare, can lead to anemia, bone problems, and neurological issues. Menkes disease is a genetic disorder of copper deficiency.
Nurses monitor for signs of copper toxicity or deficiency in patients with relevant conditions. They also manage electrolyte imbalances involving sodium and potassium and monitor patients on lithium therapy for its narrow therapeutic window and potential toxicity.

How to Approach the Question

First, identify the key terms in the question: 'mineral' and 'prosthetic group'.
Define 'prosthetic group' in the context of enzymes. A prosthetic group is a non-protein component that is tightly bound to an enzyme and is necessary for its function.
Evaluate each option based on this definition.
Recall or deduce the primary biological role of each mineral. Lithium is a drug. Sodium and Potassium are key electrolytes that act as loose activators.
Identify Copper as a known trace element that is an integral, tightly-bound component of several important enzymes, fitting the definition of a prosthetic group.

Concept Tested & Keywords

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E6 Biochemistry U Satyanarayana— Part 2 (pp 421-820 of 840) pp. 21-23, 47-49

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 181-183