title: Cyanohydrin reactions enhance glycolytic oscillations in yeast.
abstract: Synchronous metabolic oscillations can be induced in yeast by addition of glucose and removal of extracellular acetaldehyde (ACAx). Compared to other means of ACAx removal, cyanide robustly induces oscillations, indicating additional cyanide reactions besides ACA to lactonitrile conversion. Here, (13)C NMR is used to confirm our previous hypothesis, that cyanide directly affects glycolytic fluxes through reaction with carbonyl-containing compounds. Intracellularly, at least 3 cyanohydrins were identified. Extracellularly, all signals could be identified and lactonitrile was found to account for ~66% of total cyanide removal. Simulations of our updated computational model show that intracellular cyanide reactions increase the amplitude of oscillations and that cyanide addition lowers [ACA] instantaneously. We conclude that cyanide provides the following means of inducing global oscillations: a) by reducing [ACAx] relative to oscillation amplitude, b) by targeting multiple intracellular carbonyl compounds during fermentation, and c) by acting as a phase resetting stimulus.
authors: Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address: bohald@sund.ku.dk.
authors: Bjørn Olav
authors: BO
authors: Hald
authors: Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
authors: Astrid Gram
authors: AG
authors: Nielsen
authors: Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
authors: Christian
authors: C
authors: Tortzen
authors: Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
authors: Preben Graae
authors: PG
authors: Sørensen
mesh_terms: D000079:Acetaldehyde / Q000737:chemistry; D005285:Fermentation; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D006019:Glycolysis; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009570:Nitriles / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D009570:Nitriles; C430593:cyanohydrin; D000079:Acetaldehyde; D005947:Glucose
keywords: Modeling; NMR; Oscillations; Yeast