Final answer:
The approximate isoelectric point of the peptide AWAYLHTAEDM is 4.0. Therefore, correct option is a.
Step-by-step explanation:
The isoelectric point (pI) of a peptide is the pH at which it carries no net charge. To determine the approximate pI of the peptide AWAYLHTAEDM, we need to consider the pKa values of the amino acids in the peptide. The pI can be estimated by averaging the pKa values of the ionizable groups that are present in the peptide.
The three most common amino acids in the peptide AWAYLHTAEDM are Alanine (A), Aspartic Acid (D), and Glutamic Acid (E). The pKa values for these amino acids are approximately 2.34, 3.65, and 4.25, respectively.
Since the peptide contains negatively charged amino acid side chains (D and E), we can expect the pI to be closer to the lower end of the pH range, which is 4.0 (option a). So, the approximate isoelectric point of the peptide AWAYLHTAEDM is option a) 4.0.