ABSTRACT
This chapter provides an overview of current knowledge on fatty acid biosynthesis, including the source of carbon, the enzymes of synthesis and termination, and their regulation. Fatty acids are assembled by sequential additions of two carbon units which are derived from acetate. To serve as "primer" for the first condensation reaction of fatty acid synthesis acetate must first be activated to form acetyl-coenzyme A (CoA). Acetyl-CoA may be produced from pyruvate and CoA by the pyruvate dehydrogenase reaction. The pyruvate dehydrogenase complex (PDC) has been extensively studied in plant mitochondria, but much less is known about PDC in plastids, particularly in chloroplasts. Acetyl-CoA carboxylase (ACCase) catalyzes the first step of fatty acid biosynthesis. This step is often considered to be the committed step for plastidial de novo fatty acid biosynthesis because the malonyl-CoA produced in the plastid is used predominately, if not exclusively, for the synthesis of fatty acids.
