Figure 1. A pathway designed to produce PHBV in the plastids of
plants. Propionyl-CoA is derived from threonine via threonine
deaminase and the pyruvate dehydrogenase complex. Acetyl-CoA is
drawn from normal intermediary metabolism. The pathway requires
transformation of the plant with four genes (ilvA, bktB, phbB, and
phbC), and relies on endogenous pyruvate dehydrogenase. All
enzymes encoded by transgenes are targeted to the plastid using
chloroplast transit peptides.