Which of the following is the earliest discovered amino acid ?

Options

A. Glycine
B. Methionine
C. Phenylalanine
D. Asparagine.

Answer

To determine the earliest discovered amino acid from the given options, we can follow these steps:

### Step 1: Identify the Amino Acids
We have four amino acids to consider:
1. Glycine
2. Methionine
3. Phenylalanine
4. Asparagine

### Step 2: Research the Discovery Dates
We need to find out when each amino acid was first isolated:
- **Glycine**: Isolated in 1820 from gelatin.
- **Methionine**: Isolated in 1922 from casein.
- **Phenylalanine**: Isolated in 1881 from lupine seeds.
- **Asparagine**: Isolated in 1932 from asparagus.

### Step 3: Compare the Dates
Now, we compare the years of discovery:
- Glycine (1820) - earliest
- Phenylalanine (1881)
- Methionine (1922)
- Asparagine (1932)

### Step 4: Conclusion
From the comparison, we can see that Glycine was the first amino acid to be discovered in 1820, making it the earliest discovered amino acid among the options provided.

### Final Answer
The earliest discovered amino acid is **Glycine**.

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