Figure 5.The biosynthetic pathway from campesterol to brassinolide showing known mutants in Arabidopsis that block the conversion of intermediates at the steps indicated, or prevent BR perception and/or signal transduction. The pathway on the left is termed Early C-6 Oxidation and that on the right, Late C-6 Oxidation. BR-6-Oxidase has been shown to convert 6-Deoxocastasterone and 6-Deoxotyphasterol to the corresponding 6-oxo compounds in Arabidopsis, while the conversion of 3-Dehydro-6-deoxoteasterone and 6-Deoxoteasterone has been demonstrated so far in recombinant yeast cells only.