Which of the following amino acids will exist as a -2 ion at very high pH?
A) arginine
B) glutamic acid
C) isoleucine
D) none of these

Question

Quizplus · Accepted Answer

Glutamic acid has a carboxyl group (-COOH) that can lose a proton at high pH, becoming a negatively charged ion (glutamate, -COO-). Arginine has a positive charge at high pH due to its guanidine group (-C(NH2)NH2+), and isoleucine does not have any ionizable groups at high pH.

Which of the Following Amino Acids Will Exist as a -2