Question

Apolipoprotein E is rich in which amino acid?

• A. Lysine
• B. Arginine
• C. Histidine
• D. Methionine

Hint:

Apo-E is the arginine-rich apoprotein of VLDL.

Answer 1

The Correct Option is B

Step 1: Apolipoprotein E (apo-E) is the protein component on remnant lipoproteins that mediates their receptor uptake. The question asks which amino acid it is especially rich in.

Step 2: Apo-E is classically described as the arginine-rich apoprotein and is isolated mainly from VLDL.

Step 3: Quantitatively, arginine makes up about 10 percent of its total amino acids, and apo-E accounts for roughly 5 to 10 percent of total VLDL apoproteins in normal people. This high arginine content is why it is named arginine-rich.

Step 4: The other choices, lysine, histidine and methionine, are not the defining residue of apo-E. Hence the correct answer is Arginine.