Regulation of sterol biosynthesis in Saccharomyces cerevisiae.

Sterol synthesis in Saccharomyces cerevisiae was primarily controlled by the growth rate. At low specific growth rates the intermediates of ergosterol biosynthesis prevailed in cells. At the same time, the total sterol content reached about 6% of dry matter whereas the content of ergosterol was only 2-2.5%, which seems to be the maximum value for S. cerevisiae. After esterification with fatty acids these sterol intermediates are stored in lipid globules together with reserve triacylglycerols. The sporulating S. cerevisiae cells contained 3.5% sterols and 1.5% ergosterol of dry matter.