Pentose phosphate pathway (WP369)

Saccharomyces cerevisiae

The pentose phosphate pathway is important for generating NADPH, which is a source of reducing energy, as well as a variety of sugar molecules that are required for the biosynthesis of nucleic acids and amino acids. (CITS:[8929392])(CITS:[8910528])(CITS:[9813062])(CITS:[ 11298766])(CITS:[1628611])(CITS:[15960801])(CITS:[7916691])(CITS:[14690456]). This pathway is also important for protecting yeast from oxidative stress, since NADPH is an essential cofactor for glutathione- and thioredoxin-dependent enzymes that defend cells against oxidative damage (CITS:[8929392])(CITS:[8910528])(CITS:[11557322])(CITS:[16179340]). The pentose phosphate pathway is of industrial interest for the fermentation of xylose to ethanol (CITS:[11916674]). Xylose is the predominant sugar found in biomass such as agricultural wastes, wood, municipal solid wastes, and wastes from pulp and paper industries, and possibly could serve as a low-cost and abundant raw material for fuel ethanol production (CITS:[8534086]). Saccharomyces cerevisiae does not naturally metabolize xylose, but recombinant S. cerevisiae strains containing the xylose reductase and xylitol dehydrogenase genes from Pichia stipitis are able to metabolize xylose via the pentose phosphate pathway (CITS:[15630585])(CITS:[8534086]). Changes in the levels of enzymes in the pentose phosphate pathway effect the fitness, ethanol production, and amount of xylose metabolized by these recombinant xylose-utilizing strains. The pentose phosphate pathway is also of medical interest because mutations in the human homologs of some yeast pentose phosphate genes are associated with a variety of diseases. Zwf1p is homologus to human glucose-6-phosphate dehydrogenase (G6PD), which has been implicated in neonatal jaundice and haemolytic anemia. Sol3p and Sol4p have similarity to human PGLS, which is associated with 6- phosphogluconolactonase deficiency and may contribute to some forms of G6PD-associated hemolytic anemia (CITS:[10518023]). Sol3p and Sol4p also have similarity to human H6PD, which is associated with cortisone reductase deficiency (CITS:[10518023]). Gnd1p and Gnd2p have similarity to human PGD, mutation in which may also contribute to some forms of G6PD-associated hemolytic anemia (CITS:[10518023]). Tal1p is similar to human TALDO1, mutation in which has been reported to be associated with transaldolase deficiency and hepatosplenomegaly (CITS:[ 8300619]). Rki1p has similarity to human RPIA, which has been associated with ribose 5-phosphate isomerase deficiency, leukoencephalopathy and peripheral neuropathy (CITS:[16054529]). SOURCE: SGD pathways, http://pathway.yeastgenome.org/server.html

Authors

Kdahlquist , Thomas Kelder , Daniela Digles , Egon Willighagen , Denise Slenter , and Eric Weitz

Activity

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Organisms

Saccharomyces cerevisiae

Communities

Annotations

Pathway Ontology

pentose phosphate pathway

Participants

Label Type Compact URI Comment
D-6-Phospho-glucono-delta-lactone Metabolite chebi:16938
6-Phosphogluconate Metabolite chebi:48928
Fructose-6-phosphate Metabolite cas:643-13-0
H2O Metabolite chebi:15377
Glyceraldehyde-3-phosphate Metabolite cas:591-57-1
D-Ribose-5-Phosphate Metabolite cas:3615-55-2
NADP Metabolite chebi:44409
Erythrose-4-phosphate Metabolite cas:585-18-2
Xylulose-5-phosphate Metabolite cas:60802-29-1
NADPH Metabolite chebi:16474
Ribulose-5-phosphate Metabolite cas:4151-19-3
Sedoheptulose-7-phosphate Metabolite cas:2646-35-7
H+ Metabolite chebi:15378
Glucose-6-phosphate Metabolite cas:59-56-3
[CO2] Metabolite chebi:16526
TKL1 GeneProduct ensembl:YPR074C
GND1 GeneProduct ensembl:YHR183W
GND2 GeneProduct ensembl:YGR256W
ZWF1 GeneProduct ensembl:YNL241C
TKL2 GeneProduct ensembl:YBR117C
RKI1 GeneProduct ensembl:YOR095C
RPE1 GeneProduct ensembl:YJL121C
SOL4 GeneProduct ensembl:YGR248W
TAL1 GeneProduct ensembl:YLR354C
SOL3 GeneProduct ensembl:YHR163W

References