Fibrin is formed from fibrinogen due to activity of

Options

A. Prothrombin
B. Active thrombin
C. Heparin
D. Antiprothrombin

Answer

To solve the question "Fibrin is formed from fibrinogen due to the activity of," we will analyze the options provided and determine which one is correct.

### Step-by-Step Solution:

1. **Understanding Fibrin and Fibrinogen**:
- Fibrinogen is a soluble plasma protein produced by the liver. It plays a crucial role in blood clotting.
- Fibrin is the insoluble protein that forms the meshwork of a blood clot.

2. **Identifying the Conversion Process**:
- The conversion of fibrinogen to fibrin is a key step in the coagulation cascade, which is essential for stopping bleeding.

3. **Analyzing the Options**:
- **Option 1: Prothrombin**:
- Prothrombin is a precursor to thrombin and is also produced by the liver. However, it does not directly convert fibrinogen to fibrin.
- **Option 2: Active Thrombin**:
- Thrombin is the enzyme that catalyzes the conversion of fibrinogen into fibrin. This is the correct answer.
- **Option 3: Heparin**:
- Heparin is an anticoagulant that prevents blood clotting. Therefore, it does not facilitate the formation of fibrin.
- **Option 4: Antiprothrombin**:
- Antiprothrombin inhibits the conversion of prothrombin to thrombin, thus also not facilitating the formation of fibrin.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Active Thrombin**, as it is the enzyme responsible for the conversion of fibrinogen to fibrin.

### Final Answer:
Fibrin is formed from fibrinogen due to the activity of **Active Thrombin**.