which of the following is acidic amino acid?

Options

A. Glycine
B. Valine
C. Leucine
D. Glutamic acid

Explanation

To determine which of the following is an acidic amino acid, we need to understand the definition and characteristics of acidic amino acids.

### Step-by-Step Solution:

1. **Definition of Acidic Amino Acids**:
- Acidic amino acids are those that contain a carboxylic acid group (-COOH) in their side chain. This additional carboxylic acid group contributes to the overall acidity of the amino acid.

2. **Identifying Examples**:
- The most common examples of acidic amino acids are **aspartic acid** and **glutamic acid**. Both of these amino acids have an extra carboxylic acid group in their side chains.

3. **Structure of Glutamic Acid**:
- The structure of glutamic acid can be represented as:
- **CH2-CH2-COOH**
- Here, the side chain (CH2-CH2-COOH) contains a carboxylic acid group (-COOH), confirming that it is indeed an acidic amino acid.

4. **Conclusion**:
- Based on the definition and examples, if the question provides options, you would identify which one includes either aspartic acid or glutamic acid. If glutamic acid is listed among the options, it is the correct answer.

### Final Answer:
- The acidic amino acid from the options provided is **glutamic acid**.