CH 461 Lecture Notes - Lecture 9: Fatty Acid Synthase, Malonyl-Coa, Malonate
Document Summary
The biosynthetic reaction pathway to a compound is usually not a simple opposite of its end of the growing fatty acid chain. All the other carbons come from the acetyl group of breakdown. In fatty acid synthesis, acetyl coa is the direct precursor only of the methyl acetyl coa but only after it is modified to provide the actual substrate for fatty acid synthase, malonyl coa. Malonyl coa contains a 3 carbon dicarboxylic acid, malonate, bound to coenzyme a. Malonate is formed from acetyl coa by the addition of co 2using the biotin cofactor of the enzyme acetyl coa carboxylase. Formation of malonyl coa is the commitment step for fatty acid synthesis, because malonyl coa has no metabolic role other than serving as a precursor to fatty acids. Fatty acid synthase (fas) carries out the chain elongation steps of fatty acid biosynthesis. In mammals, fas contains two subunits, each containing multiple enzyme activities.
