Fig. 2 in Comparison of glucosinolate diversity in the crucifer tribe Cardamineae and the remaining order Brassicales highlights repetitive evolutionary loss and gain of biosynthetic steps

Fig. 2. The essence of glucosinolate (GSL) biosynthesis as imagined for the presumably ancient 2-methylpropylGSL and a β-hydroxylated derivative, 2-hydroxy-2-methylpropylGSL. The three steps between the CYP83 product and thiohydroximic acid in general GSL biosynthesis involves glutathione, serving as the donor of sulfur. The illustrated hypothetic pathway is based on the known biosynthetic pathway of more recently evolved GSLs (Sønderby et al., 2010).