Chapter 19, Problem 19.66P

Calculate the isoelectric point for each amino acid.

a. cysteine: $\text{p}{K}_{\text{a}}\left(\text{COOH}\right)=\text{2}\text{.05; p}{K}_{\text{a}}\left({\text{α-NH}}_{\text{3}}^{+}\right)=\text{10}\text{.25}$

b. methionine: $\text{p}{K}_{\text{a}}\left(\text{COOH}\right)=\text{2}\text{.28; p}{K}_{\text{a}}\left({\text{α-NH}}_{\text{3}}^{+}\right)=9.21$