Correlation of lipid accumulation in yeasts with possession of ATP: citrate lyase

Department of Biochemistry, University of Hull, Hull HU6 7RX, U.K. ABSTRACT ATP: citrate lyase has been found in 13 strains of yeast (representing six genera) which are capable of accumulating lipid to above 20% of their biomass. The enzyme is absent in 10 other yeasts which do not accumulate lipid. The presence of the enzyme is therefore directly correlated to the phenomenon of oleaginicity. The enzyme is located in the cytosol fraction of the yeasts and is probably the sole means of producing acetyl-CoA in most oleaginous yeasts. The specific activity of the enzyme correlates with the specific rate of lipid synthesis as determined in nitrogen-limited chemostat cultures of Lipomyces starkeyi, though not with the lipid content of the cells. From this and by calculation, it may be inferred that the enzyme is possibly the rate-limiting reaction for lipid biosynthesis.