What is the process to calculate the net charge of the peptide AIGNECK at pH 4.3 using the given set of pKa values?
To find the net charge of the peptide AIGNECK at pH 4.3, we need to consider the pKa values of the acidic and basic groups in the amino acids that make up the peptide. By comparing the pH to the pKa values, we can determine the charge of each amino acid at pH 4.3 and calculate the net charge of the peptide.
Calculating Net Charge of Peptide AIGNECK
Explanation: AIGNECK is composed of amino acids A, I, G, N, E, C, and K. In order to determine the net charge of the peptide at pH 4.3, we need to look at the pKa values given for the functional groups in these amino acids.
pKa Values:
- A: -0.23
- I: +0.54
- G: -1.87
- N: +1.32
- E: Not provided
- C: Not provided
- K: Not provided
At pH 4.3, we need to evaluate the charges of the N-terminus (NH2 group) and the C-terminus (COOH group) of the peptide.
N-Terminus (NH2 group): Since there is no pKa value provided for the amino group, we assume it is basic and has a positive charge. Therefore, the N-terminus will be +1 at pH 4.3.
C-Terminus (COOH group): Given that the pKa values provided are for acidic groups, the carboxylic acid group will be negatively charged. Hence, the C-terminus will be -1 at pH 4.3.
For the remaining amino acids (A, I, G, N, E, C, and K), we are unable to determine their charges at pH 4.3 as the pKa values for their side chains are not provided.
Net Charge: Unfortunately, without knowing the pKa values of all the specific functional groups in each amino acid, we cannot accurately calculate the net charge of the peptide AIGNECK at pH 4.3 using the given set of pKa values.