In primary structure of a protein, methionine is located at left end of amino acid chain while glutamic acid is located at right end. Which of the following statement is ture with respect to above mentioned protein?

Options

A. Methionine is a C-terminal amino acid
B. Glutamic acid is the first amino acid of the chain
C. Glutamic acid is N-terminal amino acid
D. Methionine is the first amino acid of the chain

Answer

To solve the question regarding the primary structure of the protein where methionine is at the left end and glutamic acid is at the right end, we need to understand the terminology used in protein structure:

1. **Identify the ends of the amino acid chain**:
- The left end of the amino acid chain is known as the N-terminal (amino terminus), where the amino group (-NH2) is free.
- The right end of the amino acid chain is known as the C-terminal (carboxyl terminus), where the carboxyl group (-COOH) is free.

2. **Determine the positions of methionine and glutamic acid**:
- Methionine is located at the N-terminal (left end).
- Glutamic acid is located at the C-terminal (right end).

3. **Analyze the statements provided**:
- **Statement 1**: Methionine is a C-terminal amino acid.
- This is false because methionine is at the N-terminal.
- **Statement 2**: Glutamic acid is the first amino acid of the chain.
- This is true because the first amino acid in the sequence is the one at the N-terminal, which is methionine, but glutamic acid is at the C-terminal.
- **Statement 3**: Glutamic acid is the N-terminal amino acid.
- This is false because glutamic acid is at the C-terminal.
- **Statement 4**: Methionine is the first amino acid of the chain.
- This is true because methionine is at the N-terminal and is the first amino acid in the sequence.

4. **Conclusion**:
- The correct statements are that methionine is the first amino acid of the chain and glutamic acid is at the C-terminal. However, the only statement that is true in the context of the options given is that "Glutamic acid is the first amino acid of the chain" is misleading. The correct answer should be that "Methionine is the first amino acid of the chain."

### Final Answer:
The true statement with respect to the above-mentioned protein is: "Methionine is the first amino acid of the chain."