Consider the following sequence for aspartic acid: The pI (isoelectric point) of aspartic acid is:
Consider the following sequence for aspartic acid:
The pI (isoelectric point) of aspartic acid is:
$3.65$
$2.77$
$5.74$
$1.88$
Solution
At the isoelectric point of aspartic acid, we have
$$
\begin{array}{l}
{\left[\mathrm{H}_{3} \mathrm{NCH}\left(\mathrm{CH}_{2} \mathrm{COOH}ight) \mathrm{CO}_{2} \mathrm{H}ight]=\left[\mathrm{H}_{3} \stackrel{+}{\mathrm{N}} \mathrm{CH}\left(\mathrm{CH}_{2} \mathrm{COO}^{-}ight) \mathrm{CO}_{2}^{-}ight]} \\
\mathrm{pI}=\frac{1}{2}\left(\mathrm{p} K_{1}+\mathrm{p} K_{\mathrm{R}}ight)=\frac{1}{2}(1.88+3.65)=2.77
\end{array}
$$
,