延胡索酸腺苷酸琥珀酸裂合酶（ADSL）

[[N-琥珀酰-5-氨基-4-羧基咪唑核苷酸（SACAIR）]]<->[[5-氨基咪唑-4-氨甲酰核苷酸（AICAR）]]+[[C4：延胡索酸（富马酸，fumaric）]]

\usepackage{chemfig}
\begin{document}

\chemfig{
	\fbox{R}-[2,0.8]N(-[2,0.25]9)
	-[3.5,0.6](-[3.3,0.25]4)(-[4.5,0.7]N(-[2,0.25]3)(-[4,0.3]H_2))
	=[2,0.8](-[4.8,0.25]5)(-[3,0.7](=[2,0.7]O)
	(
		-[4,0.8]NH_2
			-[4,0.5]C
				(-[4,0.25]H)
				(-[6,0.5]COOH)
				(-[2,0.5]C
					(-[,0.3]H_2)
					(-[2,0.5]COOH)
				)
	)
	(-[6,0.25]6))
	-[0.5,0.8]N(-[5.5,0.25]7)(-[,0.3]H)
	=[6.55,0.8]
		(-[4,0.2]8)
		-[5.25,0.6]
}

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

\chemfig{
	\fbox{R}-[2,0.8]N(-[2,0.25]9)
	-[3.5,0.6](-[3.3,0.25]4)(-[4.5,0.7]N(-[2,0.25]3)(-[4,0.3]H_2))
	=[2,0.8](-[4.8,0.25]5)(-[3,0.7](=[2,0.7]O)
	(
		-[4.7,0.8]N(-[2,0.3]1)
		-[4,0.3]H_2
	)
	(-[6,0.25]6))
	-[0.5,0.8]N(-[5.5,0.25]7)(-[,0.3]H)
	=[6.55,0.8]
		(-[4,0.2]8)
		-[5.25,0.6]
}
+
\chemfig{
	CH
		(=[2,0.5]CH-[,0.5]COOH)
		(-[,0.5]COOH)
}

\end{document}