Question

Plasma membrane H+ - ATPases are characteristically inhibited by:

• A. NO3-
• B. Zn2+
• C. VO3-
• D. Ca2+

Hint:

VO3- inhibits these enzymes through direct binding to their active sites.

Answer 1

The Correct Option is C

Step 1: Concept
Plasma membrane H+ - ATPases

Step 2: Meaning
Enzymes responsible for the active transport of hydrogen ions (H+) across cell membranes, using ATP as an energy source.

Step 3: Analysis
Option C, VO3-, inhibits these enzymes by binding to and inactivating them. This is due to its ability to form a complex with iron in the enzyme's active site, thereby blocking substrate access and reducing its activity.

Step 4: Conclusion
The inhibition of plasma membrane H+ - ATPases by VO3- is well-documented in biological literature. Final Answer: (C)