Characterisation of the FAD2 gene family from Hiptage benghalensis: A ricinoleic acid accumulating plant

Diagrammatic representation of enzymatic activities involved in hydroxy fatty acids synthesis. Enzymatic steps in yeast cells or in plant cells are grouped in two rectangular boxes. C16:1, C16:2, C18:1, C18:2, C18:3, C20:1, C16:1-OH, 18:1-OH, C18:2-OH are C16:1Δ9, C16:2Δ9,12, C18:1Δ9, C18:2Δ9,12, C18:3Δ9,12,15, C20:1Δ11, 12OH-C16:1Δ9, 12OH-18:1Δ9 and 12OH-C18:2Δ9,15. The isolated Δ12-desaturase enzymes (HbFAD2s) can desaturate both C16:1Δ9 and C18:1Δ9 substrates, and the two isolated Hiptage benghalensis hydroxylases HbFAH12-1 and HbFAH12-2 can hydroxylate these substrates. 12OH-18:1Δ9 can be desaturated by the same FAD3 enzyme that desaturates C18:2Δ9,12 into C18:3Δ9,12,15 in plant.