A plant proteinase is
(a) papain
(b) Trypsin
(c) Pepsin
(d) Urease

Options

A. papain
B. Trypsin
C. Pepsin
D. Urease.

Answer

To determine which of the given options is a plant proteinase, we can analyze each option step by step:

1. **Understanding the term "plant proteinase":**
- A plant proteinase is an enzyme that breaks down proteins and is derived from plant sources.

2. **Analyzing the options:**
- **(a) Papain:**
- Papain is an enzyme that is isolated from papaya, a plant. It is known to break peptide bonds in proteins, leading to protein breakdown. This makes it a plant proteinase.
- **(b) Trypsin:**
- Trypsin is an enzyme that is found in the digestive system of animals. It is classified as an enteropeptidase and is involved in protein digestion. Therefore, it is not a plant proteinase.
- **(c) Pepsin:**
- Pepsin is another enzyme that breaks down proteins into smaller peptides. It is produced in the stomach of animals and is part of the digestive system. Thus, it is also not a plant proteinase.
- **(d) Urease:**
- Urease is an enzyme that hydrolyzes urea into ammonia and carbon dioxide. While it can be found in some plants, it is primarily associated with nitrogen metabolism and is not classified as a proteinase.

3. **Conclusion:**
- Among the options provided, the only enzyme that is a plant proteinase is **(a) Papain**.

Thus, the correct answer is **(a) Papain**.

---