Question

What is the likely number of amino acids in a 11 KDa protein?

• A. 90
• B. 100
• C. 110
• D. 120

Hint:

Use 110 Da as the average residue weight when estimating amino acid count from protein molecular weight in kDa.

Answer 1

The Correct Option is B

Step 1: Know the average molecular weight of an amino acid residue
On average, one amino acid has a molecular weight of approximately 110 Daltons (Da) in a polypeptide chain.

Step 2: Convert kilodaltons to Daltons
Given protein mass is 11 kilodaltons (kDa), so:
\[ 11\, \text{kDa} = 11,000\, \text{Da} \]

Step 3: Calculate number of amino acids
\[ \text{Number of amino acids} = \frac{11,000}{110} = 100 \]