Which of the following statements regarding coenzymes and prosthetic groups of enzymes is not true?

Options

A. Both are required for enzyme action
B. Both can be separated from enzyme by dialysis
C. Both are organic compounds
D. Both are not polypeptides

Answer

To determine which statement regarding coenzymes and prosthetic groups of enzymes is not true, we need to analyze each option provided in the question.

1. **Understanding Coenzymes and Prosthetic Groups**:
- Coenzymes are organic molecules that assist enzymes in catalyzing reactions. They are typically loosely bound to the enzyme and can be removed without destroying the enzyme's structure.
- Prosthetic groups, on the other hand, are also non-polypeptide units that are tightly bound to the enzyme. They are essential for the enzyme's activity and cannot be easily removed.

2. **Evaluating the Statements**:
- **Statement 1**: "Both are required for enzyme action."
- This statement is true. Both coenzymes and prosthetic groups are essential for the activity of many enzymes.
- **Statement 2**: "Both can be separated from enzyme by dialysis."
- This statement is not true. While coenzymes can sometimes be removed from enzymes, prosthetic groups are tightly bound and cannot be separated by dialysis.
- **Statement 3**: "Both are organic compounds."
- This statement is true. Both coenzymes and prosthetic groups are organic in nature.
- **Statement 4**: "Both are not polypeptides."
- This statement is true. Neither coenzymes nor prosthetic groups are polypeptides; they are distinct from the protein portion of the enzyme.

3. **Conclusion**:
- The statement that is not true is: "Both can be separated from enzyme by dialysis." This is the correct answer to the question.

**Final Answer**: The statement that is not true is: "Both can be separated from enzyme by dialysis."

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