What effect does the presence of the α-COO- group of an amino acid have on the pKₐ value of its α-NH₃⁺ group?

Question

Quizplus · Accepted Answer

The presence of the α-COO- group of an amino acid has an acidic effect on the α-NH₃⁺ group, decreasing its pKₐ value by approximately 1.5 pH units. This is because the negatively charged α-COO- group can form a salt bridge with the positively charged α-NH₃⁺ group, stabilizing the protonated form and making it more difficult to lose a proton.

What Effect Does the Presence of the α-COO- Group of an Amino