Which of the following is not a recombinant protein used in medical practice ?

Options

A. TPA (Tissue plasminogen activator)
B. Interferon
C. Vaccine for hepatitis B
D. Crystal proteins

Answer

To determine which of the following is not a recombinant protein used in medical practice, we need to analyze each option provided:

1. **Option A: TPA (Tissue Plasminogen Activator)**
- TPA is a protein that helps dissolve blood clots, particularly in cases of heart attacks. It is produced using recombinant DNA technology, making it a recombinant protein. Therefore, this option is not the correct answer.

2. **Option B: Interferon**
- Interferons are proteins that play a crucial role in the immune response, helping the body defend against pathogens. They are also produced using recombinant DNA technology. Thus, this option is also not the correct answer.

3. **Option C: Vaccine for Hepatitis B**
- The Hepatitis B vaccine is produced using recombinant DNA technology, where the surface antigen of the virus is expressed in yeast cells. This makes it a recombinant protein as well. Hence, this option is not the correct answer.

4. **Option D: Crystal Protein**
- Crystal proteins, specifically the Cry proteins produced by Bacillus thuringiensis (Bt), are naturally occurring proteins that are not produced through recombinant DNA technology. Therefore, this option is the correct answer as it is not a recombinant protein.

**Final Answer: Option D - Crystal Protein is not a recombinant protein used in medical practice.**