Align molecules above each other in chemfig and change label size

Question

I am using chemfig to draw a reaction that splits into two and then goes to one final molecules. I have managed to use nodes to get the arrows to go from the second molecule and split into the two alternatives, however, the two alternative molecules are not aligned. Secondly, I only get errors with my code if i use e.g. \tiny to get the label on the reactions arrows to be smaller in font size.

How can I align the molecules above each other? How can I change the text size?

I have made it as following:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}

\usepackage{chemfig}

    \begin{document}

    \begin{tikzpicture} 
    \setatomsep{1.4em}
    \schemestart
    \chemfig{[:210]O*3(-(-(*6(-=-=-=)))-(-)-)} 
    \arrow{<=>[x]}[,1.3,thick,teal]
    \chemfig{*6(-=-(-(<[2]\color{red}{O}H)-[-0.7](<:[-2]\color{red}{O}H)-)=-=)} 
    \arrow{<=>[enzyme]}[45,1,thick,teal]
    \chemfig{*6(-=-(-(<[2]\color{red}{O}H)-[-0.7](=[-2]\color{red}{O})-CH3)=-=)}
    \arrow{<=>[enzyme]}[-40,1,thick,teal]
    \chemfig{*6(-=-(-(=[2]\color{red}{O})-[-0.7](<:[-2]\color{red}{O}H)-CH3)=-=)}
    \arrow(@c2--.north west){<=>[enzyme]}[-45,1,thick,teal]
    \chemfig{*6(-=-(-(=[2]\color{red}{O})-[-0.7](<:[-2]\color{red}{O}H)-CH3)=-=)}
    \arrow(@c5--@c4){<=>[enzyme]}[,1,thick,teal] 
    \schemestop
    \end{tikzpicture}


    \end{document}

Answer 1

If you start the arrows from symmetric points on the @c2 molecule, i.e. from north west and south west, you can align the alternative molecules. Surrounding the reaction scheme with tikzpicture is unnecessary, as far as I know, and without the tikzpicture, you can set the label font size to \tiny just fine:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}

\usepackage{chemfig}

\begin{document}

%\begin{tikzpicture} 
    \setatomsep{1.4em}
    %\schemedebug{true}
    \schemestart
    \chemfig{[:210]O*3(-(-(*6(-=-=-=)))-(-)-)} 
    \arrow{<=>[\tiny x]}[,1.3,thick,teal]
    \chemfig{*6(-=-(-(<[2]\color{red}{O}H)-[-0.7](<:[-2]\color{red}{O}H)-)=-=)} 
    \arrow(.north east--.south west){<=>[\tiny enzyme]}[45,1,thick,teal] % added anchors
    \chemfig{*6(-=-(-(<[2]\color{red}{O}H)-[-0.7](=[-2]\color{red}{O})-CH3)=-=)}
    \arrow(.south east--.north west){<=>[\tiny enzyme]}[-45,1,thick,teal]  % added anchors, corrected angle
    \chemfig{*6(-=-(-(=[2]\color{red}{O})-[-0.7](<:[-2]\color{red}{O}H)-CH3)=-=)}
    \arrow(@c2.south east--.north west){<=>[\tiny enzyme]}[-45,1,thick,teal] % added start anchor
    \chemfig{*6(-=-(-(=[2]\color{red}{O})-[-0.7](<:[-2]\color{red}{O}H)-CH3)=-=)}
    \arrow(@c5.north [email protected] west){<=>[\tiny enzyme]}[,1,thick,teal] % added anchors
    \schemestop
%\end{tikzpicture}

\end{document}