Biosynthesis of L-ascorbic acid (vitamin C) by Saccharomyces cerevisiae.
Saccharomyces cerevisiae cells incubated with D-glucose (D-Glc), D-galactose or D-mannose (D-Man) synthesised D-erythroascorbic acid (D-EAA) but not L-ascorbic acid (L-AA). Accumulation of D-EAA was observed in cells incubated with D-arabinose (D-Ara) whilst accumulation of L-AA occurred in cells incubated with L-galactose (L-Gal), L-galactono-1,4-lactone and L-gulono-1,4-lactone. When S. cerevisiae cells were incubated with D-[U-(14)C]Glc, D-[U-(14)C]Man or L-[1-(14)C]Gal, incorporation of radioactivity into L-AA was observed only with L-[1-(14)C]Gal. Pre-incubation of yeast cells with D-Ara substantially reduced the incorporation of L-[1-(14)C]Gal into L-AA. Our results indicate that, under appropriate conditions, yeast cells can synthesise L-AA via the pathway naturally used for D-EAA biosynthesis.
Hancock
R D
RD
Scottish Crop Research Institute, Division of Biochemistry and Cell Biology, Unit of Plant Biochemistry, Invergowrie, Dundee, UK.
Galpin
J R
JR
Viola
R
R
D001205:Ascorbic Acid / Q000096:biosynthesis*; D002250:Carbon Radioisotopes; D002474:Cell-Free System / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D005691:Galactose Dehydrogenases / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D010944:Plants / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D013401:Sugar Alcohol Dehydrogenases / Q000378:metabolism
D002250:Carbon Radioisotopes; C005056:isoascorbic acid; D013401:Sugar Alcohol Dehydrogenases; D005691:Galactose Dehydrogenases; C028590:D-arabinose dehydrogenase; C047959:galactose dehydrogenase; D005947:Glucose; D008358:Mannose; D001205:Ascorbic Acid; D005690:Galactose