title: Purification, characterisation and cDNA sequencing of pyruvate decarboxylase from Zygosaccharomyces bisporus.
abstract: Cells of the wild-type yeast strain Zygosaccharomyces bisporus CBS 702 form alpha-hydroxy ketones from aromatic amino acid precursors during fermentation. Pyruvate decarboxylase (PDC, E.C. 4.1.1.1), the key enzyme of this biotransformation catalysing the non-oxidative decarboxylation of pyruvate and other 2-oxo-acids, was purified and characterised. The active enzyme is homotetrameric (alpha4) with a molecular mass of about 244 kDa. Activation of PDC by its substrate pyruvate results in a sigmoidal dependence of the reaction rate from substrate concentration (apparent Km value 1.73 mM; Hill coefficient 2.10). A cDNA library was screened using a PCR-based procedure, and a 1856 bp cDNA of PDC was identified and sequenced. The cDNA encodes a polypeptide of 563 amino acid residues (monomeric unit). Sequence alignments demonstrate high homologies (> 80%) to PDC genes from Saccharomyces cerevisiae, Kluyveromyces lactis and Kluyveromyces marxianus.
authors.affiliation: Institut für Lebensmittelchemie, Universität Hannover, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Neuser
authors.forename: H
authors.initials: H
authors.lastname: Zorn
authors.forename: U
authors.initials: U
authors.lastname: Richter
authors.forename: R G
authors.initials: RG
authors.lastname: Berger
mesh_terms: D018076:DNA, Complementary / Q000235:genetics; D005233:Fatty Alcohols / Q000378:metabolism; D015723:Gene Library; D007659:Ketones / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics; D016133:Polymerase Chain Reaction; D011767:Pyruvate Decarboxylase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015003:Yeasts / Q000201:enzymology / Q000378:metabolism; D020068:Zygosaccharomyces / Q000201:enzymology*
chemical_list: D018076:DNA, Complementary; D005233:Fatty Alcohols; D007659:Ketones; D010455:Peptides; C011159:acyloin; D011767:Pyruvate Decarboxylase