title: Threonine degradation by Serratia marcescens.
abstract: The wild strain of Serratia marcescens rapidly degraded threonine and formed aminoacetone in a medium containing glucose and urea. Extracts of this strain showed high threonine dehydrogenase and "biosynthetic" threonine deaminase activities, but no threonine aldolase activity. Threonine dehydrogenase-deficient strain Mu-910 was selected among mutants unable to grow on threonine as the carbon source. This strain did not form aminoacetone from threonine, but it slowly degraded threonine. Strain D-60, deficient in both threonine dehydrogenase and threonine deaminase, was derived from strain Mu-910 and barely degraded threonine. A glycine-requiring strain derived from the wild strain grew in minimal medium containing threonine as the glycine source, whereas a glycine-requiring strain derived from strain Mu-910 did not grow. This indicates that threonine dehydrogenase participates in glycine formation from threonine (via alpha-amino-beta-ketobutyrate) as well as in threonine degradation to aminoacetone.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D012696:Glycine Hydroxymethyltransferase / Q000378:metabolism; D009154:Mutation; D012706:Serratia marcescens / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism*; D013913:Threonine Dehydratase / Q000378:metabolism
chemical_list: D013912:Threonine; D000429:Alcohol Oxidoreductases; C023159:L-threonine 3-dehydrogenase; D012696:Glycine Hydroxymethyltransferase; D013913:Threonine Dehydratase; D005998:Glycine