Physiologically urea is produced by the action of an enzyme

Options

A. uricase
B. urease
C. arginase
D. none

Answer

To solve the question "Physiologically, urea is produced by the action of an enzyme: uricase, urease, arginase, or none," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Urea Cycle**:
- The urea cycle is a series of biochemical reactions that take place in the liver. It converts ammonia, which is toxic, into urea, which can be safely excreted from the body.

2. **Identify the Enzymes Involved**:
- The urea cycle involves several key enzymes. The relevant enzymes include:
- Carbamoyl phosphate synthase
- Ornithine transcarbamylase (also known as citrulline synthase)
- Argininosuccinate synthase
- Argininosuccinase
- Arginase

3. **Focus on the Production of Urea**:
- The specific step in the urea cycle that produces urea involves the enzyme arginase. This enzyme catalyzes the reaction where arginine is converted into ornithine and urea.

4. **Evaluate the Options**:
- Uricase is involved in the breakdown of uric acid, not urea.
- Urease is an enzyme that catalyzes the hydrolysis of urea into ammonia and carbon dioxide, not the production of urea.
- Arginase is the enzyme that directly catalyzes the formation of urea from arginine.
- Therefore, the correct answer is arginase.

5. **Conclusion**:
- The physiological production of urea is primarily due to the action of the enzyme arginase.

### Final Answer:
The correct option is **arginase**.

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