Glutamic acid contains two carboxylic acid groups (pK_a values of 2.2 and 4.2)and an amine group (pK_a 9.7). What is the pI for glutamic acid? A)3.2 B)6.0 C)6.5 D)7.0 E)none of the above

Question

Quizplus · Accepted Answer

The isoelectric point (pI) is calculated by averaging the pKa values of the two acidic groups that lose protons first. For glutamic acid, these are the two carboxylic acid groups with pKa values of 2.2 and 4.2. The pI is (2.2 + 4.2) / 2 = 3.2.

Glutamic Acid Contains Two Carboxylic Acid Groups (PKa Values of 2.2

Glutamic Acid Contains Two Carboxylic Acid Groups (PK_a Values of 2.2