You have a mixture of three amino acids : E(pI = 3.2), Y(pI = 5.7) & K(pI = 9.7). Under electro - phoresis at pH = 7.7, in which direction will each component of the mixture move ?

Options

A. E to anode, Y & K to cathode
B. E to anode, Y stationery, K to cathode
C. E to cathode, Y stationery, K to anode
D. E & Y to anode , K to cathode

Explanation

To solve the problem of determining the direction of movement of the amino acids E, Y, and K during electrophoresis at pH 7.7, we need to consider the isoelectric points (pI) of each amino acid and the pH of the solution.

### Step-by-Step Solution:

1. **Identify the Isoelectric Points (pI)**:
- E (Glutamic acid) has a pI of 3.2.
- Y (Tyrosine) has a pI of 5.7.
- K (Lysine) has a pI of 9.7.

2. **Determine the Charge of Each Amino Acid at pH 7.7**:
- The pH of the solution (7.7) is compared to the pI of each amino acid to determine their charge.
- An amino acid will be positively charged if the pH is below its pI and negatively charged if the pH is above its pI.

3. **Analyze Each Amino Acid**:
- **E (pI = 3.2)**: Since 7.7 > 3.2, E will be negatively charged.
- **Y (pI = 5.7)**: Since 7.7 > 5.7, Y will also be negatively charged.
- **K (pI = 9.7)**: Since 7.7 < 9.7, K will be positively charged.

4. **Determine the Direction of Movement**:
- In electrophoresis, negatively charged particles move towards the anode (positive electrode), while positively charged particles move towards the cathode (negative electrode).
- Therefore:
- E will move towards the anode.
- Y will move towards the anode.
- K will move towards the cathode.

5. **Conclusion**:
- E and Y (both negatively charged) will move towards the anode.
- K (positively charged) will move towards the cathode.

### Summary of Movement:
- E: Moves towards the anode (negatively charged).
- Y: Moves towards the anode (negatively charged).
- K: Moves towards the cathode (positively charged).