Of the following amino acids, which will have a pI closest to 3?
A)Cys
B)His
C)Gly
D)Asp
E)Lys

Name: Of the following amino acids, which will have a pI closest to 3? A)Cys B)His C)Gly D)Asp E)Lys
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Question

Quizplus · Accepted Answer

The pI of an amino acid is the pH at which it has no net charge. For Asp, the pKas are approximately 3.9 and 4.8, so at a pH of 3, both the carboxyl group and the amino group will be positively charged, but the net charge will be smaller than at neutral pH. Therefore, Asp will have the pI closest to 3.

Of the Following Amino Acids, Which Will Have a PI