Which of the following is an L-amino acids ?

Options

A.
B.
C.
D.

Answer

To determine which of the given amino acids is an L-amino acid, we will follow these steps:

### Step 1: Understand the D and L configuration
Amino acids can exist in two configurations: D (Dextrorotatory) and L (Levorotatory). The configuration is determined based on the arrangement of the groups around the central carbon atom (the alpha carbon).

### Step 2: Apply the Korn Rule
The Korn Rule states that we need to look at the arrangement of the groups around the alpha carbon. The groups are arranged as follows:
- COOH (Carboxylic acid group)
- R (Alkyl side chain)
- NH2 (Amine group)
- H (Hydrogen atom)

### Step 3: Determine the orientation
To determine whether the amino acid is D or L:
- Position the COOH group at the top.
- Look at the orientation of the R group:
- If the R group is on the right side, the amino acid is D.
- If the R group is on the left side, the amino acid is L.

### Step 4: Analyze the options
Now, we will analyze each option provided:
1. **Option A**: Check the arrangement. If the R group is not present or cannot be determined, this option is incorrect.
2. **Option B**: Check the arrangement. If the R group is on the right side, this is a D-amino acid, so this option is incorrect.
3. **Option C**: Check the arrangement. If the R group is on the left side, this indicates it is an L-amino acid, making this option correct.
4. **Option D**: Check the arrangement. If the R group is on the right side, this is a D-amino acid, so this option is incorrect.

### Conclusion
After analyzing all the options, we find that **Option C** is the correct answer as it represents an L-amino acid.

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