Figure 1.

Plant sterol synthesis pathway starting with the conversion of 2,3 oxidosqualene to cycloartenol by oxidosqualene cyclase (OSC). OSC enzymes are classed as cycloartenol synthase (CAS) or lanosterol synthase (LAS) depending on their first cyclic product. The main sterol synthesis pathway in plants is indicated by multiple arrows representing several enzymatic steps with detailed information on β-sitosterol conversion to stigmasterol by a C22-desaturase. The most common end sterols in plants are highlighted in gray. The lanosterol synthesis pathway, well known for animal and fungi is indicated by dotted lines as lanosterol synthesis has been reported in plants, although lanosterol was not detected in this study.