Do you know what the line angle formula for the tripeptide Ser-Ala-Asp as it would appear at pH 7?
To determine the line angle formula for the tripeptide Ser-Ala-Asp at pH 7, we need to consider the ionization state of the amino acid residues at that particular pH.
First, let's identify the ionizable groups in each amino acid residue:
1. Serine (Ser): Ser contains two ionizable groups, the carboxyl group (COOH) and the amino group (NH2). At pH 7, the carboxyl group is deprotonated (COO-) and the amino group is protonated (NH3+).
2. Alanine (Ala): Ala contains only one ionizable group, the carboxyl group. At pH 7, the carboxyl group is deprotonated (COO-).
3. Aspartic Acid (Asp): Asp also contains two ionizable groups, the carboxyl group and an additional carboxyl group on the side chain (CH2COOH). At pH 7, both carboxyl groups are deprotonated (COO-).
Now, let's combine the individual residues with their respective ionization states:
Ser-Ala-Asp at pH 7:
- Serine (Ser): HOOC-CH(NH3+)-CH2-OH
- Alanine (Ala): HOOC-CH(CH3)-COOH
- Aspartic Acid (Asp): HOOC-CH(CH2-COO-)-COOH
By combining the residues with their ionization states, we obtain the line angle formula for the tripeptide Ser-Ala-Asp at pH 7.