Question

Enzymes that utilize ATP in phosphate transfer require an alkaline earth metal (M) as the cofactor. M is:

• A. Ca
• B. Sr
• C. Be
• D. Mg

Answer 1

The Correct Option is D

To determine which alkaline earth metal acts as a cofactor for enzymes that utilize ATP in phosphate transfer, we need to consider the chemical and biological roles of alkaline earth metals.

Let's go through each option:

1. Calcium (Ca): While calcium is crucial for various biological processes, it is primarily involved in structural roles like bone formation and acts as a secondary messenger in signal transduction rather than directly participating in enzyme-catalyzed ATP phosphate transfers.
2. Strontium (Sr): Strontium is not typically involved in biological processes related to ATP as it mimics calcium in its properties; however, it plays no significant role in enzyme activity related to ATP utilization.
3. Beryllium (Be): Beryllium is not involved in biological processes due to its toxicity and does not function as an enzyme cofactor in phosphate transfer reactions.
4. Magnesium (Mg): Magnesium is an essential cofactor in stabilizing phosphate groups in ATP molecules. It plays a critical role in the activity of ATP-utilizing enzymes, participating in phosphate transfer by helping to stabilize the negative charges on the phosphate groups of ATP.

Magnesium (Mg) is widely recognized for its role in stabilizing ATP molecules in biological systems and is imperative for enzyme activities that involve ATP. The Mg²⁺ ion helps in maintaining the structural integrity of the ATP molecule by coordinating with the oxygen atoms of the phosphate groups, thereby facilitating successful phosphate transfer during enzymatic reactions.

Thus, the correct answer is Mg (Magnesium), as it is indeed the alkaline earth metal required by enzymes for ATP utilization in phosphate transfer.