title: Cellular content of the Krebs cycle keto acids in yeasts grown on different nitrogen sources, including hydroxylamine.
abstract: The cellular pool of Krebs cycle keto acids was followed as a function of growth in three yeasts. The keto acids were analyzed as silylated methoximes by quantitative gas chromatography with capillary glass columns. The 2-oxoglutaric acid content was strikingly high in the hydroxylamine (HA)-tolerant, HA-utilizing Endomycopsis lipolytica when compared to that in the nitrate-utilizing yeast Cryptococcus albidus and Saccharomyces cerevisiae, requiring fully reduced nitrogen for growth. The content of E. lipolytica increased throughout the log phase to maxima of about 200-250 microgram per g dry weight in HA and ammonia media. These amounts are 20-25 times greater than those attained in the two other yeasts. The cellular content of pyruvic acid was at a maximum early in the log phase, amounting to 50-70 microgram per g dry weight for all yeasts. The oxalacetic acid content never exceeded 9 microgram per g dry weight in any of the yeasts. Oximeformation, for which keto acid production is a prerequisite, is discussed as part of the HA-tolerance.
mesh_terms: D000645:Ammonium Sulfate / Q000378:metabolism; D001203:Ascomycota / Q000378:metabolism*; D002952:Citric Acid Cycle; D003454:Cryptococcus / Q000378:metabolism*; D006898:Hydroxylamines / Q000378:metabolism*; D007651:Keto Acids / Q000096:biosynthesis*; D007656:Ketoglutaric Acids / Q000096:biosynthesis; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010071:Oxaloacetates / Q000378:metabolism; D011773:Pyruvates / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D004718:Saccharomycetales / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D006898:Hydroxylamines; D007651:Keto Acids; D007656:Ketoglutaric Acids; D009566:Nitrates; D010071:Oxaloacetates; D011773:Pyruvates; D009584:Nitrogen; D000645:Ammonium Sulfate