Metabolic interconversion of free sterols and steryl esters in Saccharomyces cerevisiae

• DOI: 10.1128/jb.136.2.531-537.1978
• Publication Date: 2020-01-03T16:27:02Z
• Authors: F R Taylor; L W Parks
• Keywords: Ergosterol; Mevalonic acid; Free form

The interconversion of free and esterified sterols was followed radioisotopically with [U-14C]acetate [methyl-14C]methionine. In pulse-chase experiments, radioactivity first appeared mainly in unesterified exponential-phase cells. Within one generation time, the label equilibrated between sterol pools subsequently accumulated steryl esters stationary-phase When were prelabeled by growing cells aerobically to stationary phase diluted into unlabeled medium, returned form under several conditions. (i) During aerobic growth, decreased from 80% 45% early exponential then as culture reached phase. (ii) Under anaerobic conditions, percentage declined continuously. growth stopped, only 15% remained esterified. (iii) presence an inhibitor biosynthesis, which causes accumulation a precursor ergosterol, 40% while found preferentially form. These results indicate that bulk ester are freely interconvertible, serving supply sterols. Furthermore, there is active cellular control over what types pools.