谷氨酰胺合成酶（GS）

glutamine synthetase GS

^+$+[[0. 谷氨酸（Glu，麸氨酸，glutamate）]]+ATP->[[C5：谷氨酰胺（Gln，glutamine）]]+ADP+$+^+$

\usepackage{chemfig}
\begin{document}

\chemfig{
NH_4^+
}
+
\chemfig{
HO-[1,0.5](=[2,0.5]O)(-[7,0.5]-[1,0.5]-[7,0.5](<[6,0.8]NH_2)(-[1,0.5](=[2,0.5]O)(-[7,0.5]OH)))
}
+ATP

\begin{tikzpicture} 
\draw [<->] (0,0) to node[above] {GS} (1,0); 
\end{tikzpicture}

\chemfig{
H_2N-[1,0.5](=[2,0.5]O)(-[7,0.5]-[1,0.5]-[7,0.5](<[6,0.8]NH_2)(-[1,0.5](=[2,0.5]O)(-[7,0.5]OH)))
}
+ADP+$+^+$

\end{document}