Metabolism of 2-oxoaldehydes in yeasts. Possible role of glycolytic bypath as a detoxification system in L-threonine catabolism by Saccharomyces cerevisiae.
L-Threonine catabolism by Saccharomyces cerevisiae was studied to determine the role of glycolytic bypath as a detoxyfication system of 2-oxoaldehyde (methylglyoxal) formed from L-threonine catabolism. During the growth on L-threonine as a sole source of nitrogen, a large amount of aminoacetone was accumulated in the culture. The enzymatic analyses indicated that L-threonine was converted into either acetaldehyde and glycine by threonine aldolase or 2-aminoacetoacetate by NAD-dependent threonine dehydrogenase. Glycine formed was condensed with acetyl-CoA by aminoacetone synthase to form 2-aminoacetoacetate, a labile compound spontaneously decarboxylated into aminoacetone. The enzyme activities of the glycolytic bypath of the cells grown on L-threonine were considerably higher than those of the cells grown on ammonium sulfate as a nitrogen source. The result indicated the possible role of glycolytic bypath as a detoxification system of methylglyoxal formed from L-threonine catabolism.
D000105:Acetyl Coenzyme A / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000447:Aldehydes / Q000378:metabolism*; D005998:Glycine / Q000378:metabolism; D012696:Glycine Hydroxymethyltransferase / Q000378:metabolism; D006019:Glycolysis; D008956:Models, Chemical; D009243:NAD / Q000378:metabolism; D011765:Pyruvaldehyde / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism*
D000447:Aldehydes; D009243:NAD; D013912:Threonine; D000105:Acetyl Coenzyme A; D011765:Pyruvaldehyde; D000429:Alcohol Oxidoreductases; C023159:L-threonine 3-dehydrogenase; D012696:Glycine Hydroxymethyltransferase; D005998:Glycine