\documentclass[12pt,border=1pt,tikz,class=scrartcl,multi=false]{standalone} \usepackage{times} \usepackage[T1]{fontenc} \usepackage[latin1]{inputenc} \usepackage{mathtools,amssymb} \usepackage{pgfplots} \pgfplotsset{compat=1.12} \usetikzlibrary{positioning,calc,arrows,fit,backgrounds,decorations.text,shapes} \usepackage{chemfig,chemmacros} \renewcommand*{\familydefault}{\sfdefault} \renewcommand*\printatom[1]{\ensuremath{\mathsf{#1} } } \setatomsep{1.7em} \setdoublesep{.6ex} \setarrowdefault{,1,ultra thick} \setbondstyle{very thick,cap=but} \definesubmol\nobond{-[,0.2,,,draw=none]} \pagestyle{empty} \thispagestyle{empty} \begin{document} \renewcommand{\baselinestretch}{.5} \begin{tikzpicture} [>=latex,inner sep=2pt] \node (l1) {\chemfig{ O=[::30](-[::-60]OH)-[::60](-[::-60]NH_2) <:[::60]-[::60] *5(-*6(-=-=-=)--[,,,2]HN-=) } }; \node at ($(l1)+(8.5,0)$) (r1) {\chemfig{ O=[::30](-[::-60]OH)-[::60](-[::-60]NH_2) <:[::60]-[::60](=[::60,,,,red]\color{red}{O}) -[::-60]*6(=-=-=(-NH-[::-60](-[::-60,,,,red]\color{red}{H})=[::60,,,,red]\color{red}{O})-) } }; \node at ($(l1)-(0,5)$) (l2) {\chemfig{ O=[::30](-[::-60]OH)-[::60](-[::-60]NH_2) <:[::60]-[::60] *5(-*6(-=(-[,,,,red]\color{red}{H}|\color{red}{O})-=-=)--[,,,2]HN-=) } }; \node at ($(l2)-(0,5)$) (l3) {\chemfig{ NH_2-[:-150,,,,red]-[::-60,,,,red]-[::60] *5(-*6(-=(-HO)-=-=)--[,,,2]HN-=) } }; \node at ($(l3)-(0,5)$) (l4) {\chemfig{ \color{red}{CH_3}-[:-150,,,,red](=[::60,,,,red]\color{red}{O})-[::-60,,,,red]\chemabove{N}{H} -[::60]-[::-60]-[::60] *5(-*6(-=(-HO)-=-=)--[,,,2]HN-=) } }; \node at ($(l4)-(0,5)$) (l5) {\chemfig{ CH_3-[:-150](=[::60]O)-[::-60]\chemabove{N}{H} -[::60]-[::-60]-[::60] *5(-*6(-=(-O-[::60,1.5,,,red]\color{red}{H_3C})-=-=)--[,,,2]HN-=) } }; \node at ($(l2)+(8.5,0)$) (r2) {\chemfig{ O=[::30](-[::-60]OH)-[::60](-[::-60]NH_2) <:[::60]-[::60](=[::60]O) -[::-60]*6(=-=-=(-\color{red}{N}|\color{red}{H_2})-) } }; \node at ($(l3)+(8.5,0)$) (r3) {\chemfig{ O=[2](-[::-60]OH)-[::60] *6(-=-\color{red}{C}(-[4,.6,,,draw=none]\color{red}{OH}) -[,,,,draw=none]\color{red}{C}(-[4,.7,,,draw=none]\color{red}{HO_2})-(-NH_2)=) } }; \node at ($(l4)+(8.5,0)$) (r4) {\chemfig{ *6(-[,,,,red]\color{red}{N} =(-(-[::60]OH)=[::-60]O) -(-(-[::-60]OH)=[::60]O) =-=) } }; \node at ($(l5)+(8.5,0)$) (r5) {\chemfig{ *6(-N =[,,,,red]-[,,,,red](-(-[::-60]OH)=[::60]O) =-=) } }; \node [below=.1em of l5] {\textbf{melatonin} }; \node [below=.1em of r5] {\textbf{niacin} }; \draw [->,very thick] (l1.east) -- (r1.west) node [pos=.5,above] {\footnotesize Indoleamine} node [pos=.5,below] {\footnotesize 2,3--dioxygenase}; \draw [->,very thick] ($(l1.south)-(0,.2)$) node [left] {\textbf{L-tryptophan} } -- ($(l2.north)-(0,.5)$) node [pos=.5,right,text width=5em,text centered] {\footnotesize tryptophan hydroxylase}; \draw [->,very thick] ($(l2.south)-(0,.2)$) -- ($(l3.north)-(0,.7)$) node [pos=0,left,text width=5em] {\footnotesize5--hydroxy--tryptophan} node [pos=.5,right,text centered,text width=6em] {\footnotesize aromatic amino acid carboxylase}; \draw [->,very thick] ($(l3.south)-(0,.2)$) -- ($(l4.north)-(0,.7)$) node [pos=0.1,left=1,text width=5em] {\footnotesize5--hydroxy--tryptamine\\(5-HT)} node [pos=0,above right=1,text width=5em] {\textbf{serotonin} } node [pos=.5,right,text centered,text width=6em] {\footnotesize N--acetyl transferase}; \draw [->,very thick] ($(l4.south)-(0,.2)$) -- ($(l5.north)-(0,.7)$) node [pos=0.1,left=1,text width=4em] {\footnotesize N--acetyl 5--HT} node [pos=.5,right,text centered,text width=8em] {\footnotesize5--hydroxyindole--\\O--methyltransferase}; \draw [->,very thick] ($(r1.south)-(0,.2)$) -- ($(r2.north)-(0,.5)$) node [pos=.5,right,text centered,text width=6em] {\footnotesize formamidase}; \node [right=0pt of r1,text width=5em] {\footnotesize N'--formyl--\\kynurenine}; \draw [->,ultra thick] ($(r2.south)-(0,.2)$) -- (r3.north); \node [right=0pt of r2,text width=5em] {\footnotesize kynurenine}; \draw [->,very thick] ($(r3.south)-(0,.2)$) -- ($(r4.north)-(0,.5)$) node [pos=.5,right,text centered,text width=6em] {\footnotesize non-enzymatic\\cyclization}; \node [right=0pt of r3,text width=6em] {\footnotesize2--amino--3--(3--oxoprop--1--enyl)--fumaric acid}; \draw [->,ultra thick] ($(r4.south)-(0,.2)$) -- (r5.north); \node [right=0pt of r4,text width=5em] {\footnotesize quinolinate}; \end{tikzpicture} \end{document}