A new amino acid with a basic side chain has been identified with the following pka values:pKa (-COOH) = 2.10pKa (-NH3+) = 9.44pKa (basic side chain) = 10.51What is the charge at pH = 1.50? (you don't have to include the "+" for positive charges but you do need to include the "-" for negative charges)
Question
A new amino acid with a basic side chain has been identified with the following pka values:pKa (-COOH) = 2.10pKa (-NH3+) = 9.44pKa (basic side chain) = 10.51What is the charge at pH = 1.50? (you don't have to include the "+" for positive charges but you do need to include the "-" for negative charges)
Solution
At a pH of 1.50, the amino acid will be fully protonated because the pH is lower than all the pKa values.
The carboxyl group (-COOH) will be in its protonated form (-COOH) and will have a charge of 0.
The amino group (-NH3+) will also be in its protonated form (-NH3+) and will have a charge of +1.
The basic side chain will also be in its protonated form and will have a charge of +1.
Therefore, the total charge of the amino acid at pH 1.50 will be +2.
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