Sterol pathway in yeast. Identification and properties of mutant strains defective in mevalonate diphosphate decarboxylase and farnesyl diphosphate synthetase.

Yeast mutant strains auxotrophic for ergosterol and blocked in mevalonate diphosphate decarboxylase (erg19) and farnesyl diphosphate (FPP) synthetase (erg20) were isolated. The main feature of the mutants blocked in FPP synthetase is their ability to excrete prenyl alcohols, such as geraniol and farnesol. The isolation of the functional ERG20 gene allowed us to show that farnesyl diphosphate synthetase could be a rate limiting enzyme in ergosterol biosynthesis in yeast.