title: Metabolic flux analysis of the sterol pathway in the yeast Saccharomyces cerevisiae.
abstract: The yeast Saccharomyces cerevisiae is a useful model system for examining the biosynthesis of sterols in eukaryotic cells. To investigate underlying regulation mechanisms, a flux analysis of the ergosterol pathway was performed. A stoichiometric model was derived based on well known biochemistry of the pathway. The model was integrated in the Software COMPFlux which uses a global optimization algorithm for the estimation of intracellular fluxes. Sterol concentration patterns were determined by gas chromatography in aerobic and anaerobic batch cultivations, when the sterol metabolism was suppressed due to the absence of oxygen. In addition, the sterol concentrations were observed in a cultivation which was shifted from anaerobic to aerobic growth conditions causing the sterol pools in the cell to be filled. From time-dependent flux patterns, possible limitations in the pathway could be localized and the esterification of sterols was identified as an integral part of regulation in ergosterol biosynthesis.
authors.affiliation: Department of Bioprocess Engineering, Institute of Biotechnology, Technical University of Berlin, ACK 24, Ackerstr. 71-76, 13355, Berlin, Germany. Peter.Goetz@TU-Berlin.de
authors.forename: Judith
authors.initials: J
authors.lastname: Maczek
authors.forename: Stefan
authors.initials: S
authors.lastname: Junne
authors.forename: Peter
authors.initials: P
authors.lastname: Nowak
authors.forename: Peter
authors.initials: P
authors.lastname: Goetz
mesh_terms: D003198:Computer Simulation; D004875:Ergosterol / Q000378:metabolism*; D008954:Models, Biological; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D004875:Ergosterol