Fatty-acyl-CoA synthase, or more commonly known as yeast fatty acid synthase (and not to be confused with long chain fatty acyl-CoA synthetase), is an enzyme complex responsible for fatty acid biosynthesis, and is of Type I Fatty Acid Synthesis (FAS). Yeast fatty acid synthase plays a pivotal role in fatty acid synthesis. It is a 2.6 MDa barrel shaped complex and is composed of two, unique multi-functional subunits: alpha and beta.[2] Together, the alpha and beta units are arranged in an α6β6 structure.[3][4] The catalytic activities of this enzyme complex involves a coordination system of enzymatic reactions between the alpha and beta subunits. The enzyme complex therefore consists of six functional centers for fatty acid synthesis.[3][5]