Question

Consider the following sequence for aspartic acid : The pI (isoelectric point) of aspartic acid is :

• A. 1.88
• B. 3.65
• C. 5.74
• D. 2.77

Answer 1

Answer: (D)

2.77

Answer 2

$PH=\frac{pK_{1}+pK_{2}}{2}$
$=\frac{1.88+3.65}{2}$
$=\frac{5.53}{2}$
$=2.765 \approx 2.77$
At Isoelectric point of Aspartic Acid both carboxylic as well as amino from co-exist.