Chapter 6 Fatty acid synthesis in eukaryotes

Publisher Summary This chapter focuses primarily on the structure of fatty acids, their mechanism of action, and regulation of the enzymes responsible for the biosynthesis of long-chain saturated fatty acids, de novo. In eukaryotes, the enzymes required for fatty acid synthesis de novo are integrated into large multifunctional polypeptides that are located in the cytosol. However, the domain organization and overall molecular architecture of the animal and yeast complexes are quite different. Fatty acids fulfill several crucial roles in animals, represent a major storage form of energy, and provide an essential structural component of membranes. In animals, the catalytic components required for the entire fatty acid biosynthetic pathway are integrated into two multifunctional polypeptides: acetyl- coenzyme A (CoA) carboxylase (ACC) and fatty acid synthase (FAS). The expression of both enzymes is regulated at the transcriptional level, in a tissue-specific manner, and in response to various developmental, nutritional, and hormonal signals. Substantial progress has been made to identify the various trans-acting factors that regulate transcription of the ACC and FAS genes in response to nutritional stimuli, and many of the remaining details of these processes are likely to be elaborated in the near future.