$\mathop {\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{COOH\,\,} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{H - C - OH\,\,\,\,\,\,\,\,\,\,\,} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}} \\
{Br - C - H\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\,\,\,COOC{H_3}}
\end{array}}\limits_{(I)} $ $\mathop {\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,COOC{H_3}\,\,} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{H - C - Br\,\,\,\,\,\,\,\,\,\,\,} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}} \\
{HO - C - H\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\,\,\,\,\,\,\,COOH\,\,\,\,\,\,\,\,}
\end{array}}\limits_{(II)} $
$(a)$ isoleucine
$(b)$ cysteine
$(c)$ lysine
$(d)$ methionine
$(e)$ glutamic acid