title: Identification of Saccharomyces cerevisiae GLY1 as a threonine aldolase: a key enzyme in glycine biosynthesis.
abstract: Determination of enzyme-specific activities revealed that GLY1 encodes a threonine aldolase (TA) in Saccharomyces cerevisiae. A knock-out mutant auxotrophic for glycine lacked detectable activity. After transformation with YEp24GLY1 glycine prototrophy was restored and TA-specific activity was 16-fold higher than in the wild type. Growth experiments using glucose as the sole carbon source showed that GLY1 is more important for glycine biosynthesis than SHM1 and SHM2 encoding alternative serine hydroxymethyltransferases. On ethanol as carbon source simultaneous disruption of GLY1, SHM1 and SHM2 did not lead to glycine auxotrophy because glycine biosynthesis proceeds via alanine glyoxylate aminotransferase.
authors.affiliation: Institut für Biotechnologie 1, Forschungszentrum Jülich, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Monschau
authors.forename: K P
authors.initials: KP
authors.lastname: Stahmann
authors.forename: H
authors.initials: H
authors.lastname: Sahm
authors.forename: J B
authors.initials: JB
authors.lastname: McNeil
authors.forename: A L
authors.initials: AL
authors.lastname: Bognar
mesh_terms: D000410:Alanine Transaminase / Q000378:metabolism; D000446:Aldehyde-Lyases; D000431:Ethanol / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005998:Glycine / Q000096:biosynthesis*; D012696:Glycine Hydroxymethyltransferase / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008956:Models, Chemical; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D000637:Transaminases
chemical_list: D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D012696:Glycine Hydroxymethyltransferase; D000637:Transaminases; D000410:Alanine Transaminase; C019635:Alanine-glyoxylate transaminase; D000446:Aldehyde-Lyases; C086382:GLY1 protein, S cerevisiae; D005947:Glucose; D005998:Glycine