Particle Involvement in Fatty Acid Synthesis in Liver and Yeast Systems

Abstract

THE synthesis of fatty acids from acetate has been shown to occur in particle-free supernatant fractions obtained from a variety of mammalian tissues^1–3. An examination of the literature^4–7 reveals that such synthesis is significantly increased in the presence of a microsomal fraction. (While the term microsome may be used to describe the particle fraction prepared from liver, it is premature to refer to yeast particles by this name since the cytological fractionation of the yeast cell is less well established. As used here, the term particles refers to the fraction sedimented, after prior removal of the mitochondrial fraction, at 100,000g for 45 min. ‘Supernatant’ refers to the solution obtained after removal of the 100,000g pellet.) We have shown, for example, that the addition of rat liver microsomes, in appropriate amounts, results in an increase in the incorporation of acetate carbon into fatty acids many times greater than that observed with the rat liver supernatant fraction alone⁸. Similar observations have been made with a yeast system⁹.