zymosterol biosynthesis
gomodel:YeastPathways_PWY-6074-1
Zymosterol biosynthesis in Saccharomyces cerevisiae S288C converts lanosterol to zymosterol through ERG11, ERG24, ERG25, ERG26, and ERG27 sterol oxidation, reduction, and decarboxylation activities.
- Pathway type
- lipid biosynthesis
- Organism scope
Pathway network
46 nodes · 102 asserted directed edges
Arrows show recorded subject → object relationships, not necessarily metabolic flow. Select a node for details or an arrow for evidence. Scroll, zoom or find a node to explore.
- Reaction / activity
- Chemical / cofactor
- Protein / complex
- Cell / process context
- Solid arrow: mechanistic relation
- Dashed arrow: membership, location or cofactor relation
Components and activities
| Node | Kind or role | Source direction |
|---|---|---|
Saccharomyces cerevisiae S288CNCBITaxon:559292 | taxon | |
ERG25 ScerSGD:S000003292 | protein | |
waterCHEBI:15377 | small molecule | |
zymosterol biosynthetic processGO:0036197 | biological process | |
ERG11 ScerSGD:S000001049 | protein | |
hydronCHEBI:15378 | small molecule | |
NAD(P)HCHEBI:13392 | small molecule | |
NADP(3-)CHEBI:58349 | small molecule | |
cytosolGO:0005829 | cellular component | |
NADPH(4-)CHEBI:57783 | small molecule | |
4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-olCHEBI:17813 | lipid | |
zymosteroneCHEBI:52386 | lipid | |
3-dehydro-4alpha-methylzymosterolCHEBI:136486 | lipid | |
NAD(P)(+)CHEBI:13390 | small molecule | |
dioxygenCHEBI:15379 | small molecule | |
formateCHEBI:15740 | small molecule | |
4alpha-hydroxymethyl-4beta-methylzymosterolCHEBI:87289 | lipid | |
ERG27 ScerSGD:S000004090 | protein | |
4alpha-methylzymosterolCHEBI:1949 | lipid | |
ERG24 ScerSGD:S000005224 | protein | |
14-demethyllanosterolCHEBI:18364 | lipid | |
4alpha-carboxyzymosterol(1-)CHEBI:143575 | small molecule | |
4alpha-hydroxymethylzymosterolCHEBI:146130 | lipid | |
4alpha-formylzymosterolCHEBI:146131 | lipid | |
carbon dioxideCHEBI:16526 | small molecule | |
ERG26 ScerSGD:S000002969 | protein | |
4beta-methylzymosterol-4alpha-carboxylateCHEBI:64925 | small molecule | |
4beta-methylzymosterol-4-carbaldehydeCHEBI:87287 | lipid | |
lanosterolCHEBI:16521 | lipid | |
zymosterolCHEBI:18252 | lipid | |
endoplasmic reticulum membraneGO:0005789 | cellular component | |
lipid dropletGO:0005811 | cellular component | |
membraneGO:0016020 | cellular component | |
iron cationCHEBI:24875 | cofactor | |
hemeCHEBI:30413 | cofactor | |
sterol 14-demethylase activitygomodel:RXN3O-9820 | molecular activity | |
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | molecular activity | |
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | molecular activity | |
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | molecular activity | |
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | molecular activity | |
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | molecular activity | |
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | molecular activity | |
Delta14-sterol reductase activitygomodel:RXN66-306 | molecular activity | |
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | molecular activity | |
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | molecular activity | |
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | molecular activity | |
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | molecular activity |
Mechanistic edges
| Subject | Predicate and description | Object | Evidence |
|---|---|---|---|
ERG25 ScerSGD:S000003292 | enables | C-4 methylsterol oxidase activitygomodel:RXN3O-9826 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | has_output | waterCHEBI:15377 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | part_of | zymosterol biosynthetic processGO:0036197 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | part_of | zymosterol biosynthetic processGO:0036197 |
|
ERG11 ScerSGD:S000001049 | enables | sterol 14-demethylase activitygomodel:RXN3O-9820 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_input | hydronCHEBI:15378 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | has_input | NAD(P)HCHEBI:13392 |
|
Delta14-sterol reductase activitygomodel:RXN66-306 | has_output | NADP(3-)CHEBI:58349 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | has_input | hydronCHEBI:15378 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | has_input | NADPH(4-)CHEBI:57783 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | has_output | NAD(P)HCHEBI:13392 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | has_output | waterCHEBI:15377 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_output | 4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-olCHEBI:17813 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | part_of | zymosterol biosynthetic processGO:0036197 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | has_input | zymosteroneCHEBI:52386 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | has_input | 3-dehydro-4alpha-methylzymosterolCHEBI:136486 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | has_output | NAD(P)(+)CHEBI:13390 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | has_input | dioxygenCHEBI:15379 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | has_output | NAD(P)(+)CHEBI:13390 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_output | formateCHEBI:15740 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | has_input | NADPH(4-)CHEBI:57783 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | has_input | 4alpha-hydroxymethyl-4beta-methylzymosterolCHEBI:87289 |
|
ERG25 ScerSGD:S000003292 | enables | C-4 methylsterol oxidase activitygomodel:RXN3O-9821 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | part_of | zymosterol biosynthetic processGO:0036197 |
|
ERG27 ScerSGD:S000004090 | enables | 3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | has_input | NAD(P)HCHEBI:13392 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | has_output | NAD(P)(+)CHEBI:13390 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | part_of | zymosterol biosynthetic processGO:0036197 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | has_output | NADP(3-)CHEBI:58349 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | has_input | dioxygenCHEBI:15379 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | part_of | zymosterol biosynthetic processGO:0036197 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | has_input | dioxygenCHEBI:15379 |
|
ERG27 ScerSGD:S000004090 | enables | 3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | has_output | 4alpha-hydroxymethyl-4beta-methylzymosterolCHEBI:87289 |
|
ERG25 ScerSGD:S000003292 | enables | C-4 methylsterol oxidase activitygomodel:RXN3O-9824 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | has_output | waterCHEBI:15377 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | has_input | 4alpha-methylzymosterolCHEBI:1949 |
|
ERG24 ScerSGD:S000005224 | enables | Delta14-sterol reductase activitygomodel:RXN66-306 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | has_input | 14-demethyllanosterolCHEBI:18364 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | part_of | zymosterol biosynthetic processGO:0036197 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | has_output | 4alpha-carboxyzymosterol(1-)CHEBI:143575 |
|
Delta14-sterol reductase activitygomodel:RXN66-306 | has_input | NADPH(4-)CHEBI:57783 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | has_input | 4alpha-hydroxymethylzymosterolCHEBI:146130 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_output | NADP(3-)CHEBI:58349 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | has_output | 4alpha-formylzymosterolCHEBI:146131 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | has_input | dioxygenCHEBI:15379 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | has_output | NAD(P)HCHEBI:13392 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | has_output | waterCHEBI:15377 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | has_output | NAD(P)(+)CHEBI:13390 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | part_of | zymosterol biosynthetic processGO:0036197 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | has_output | carbon dioxideCHEBI:16526 |
|
ERG26 ScerSGD:S000002969 | enables | 3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | has_output | waterCHEBI:15377 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_input | NADPH(4-)CHEBI:57783 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_input | dioxygenCHEBI:15379 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | has_input | dioxygenCHEBI:15379 |
|
ERG25 ScerSGD:S000003292 | enables | C-4 methylsterol oxidase activitygomodel:RXN3O-9823 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | has_input | NAD(P)HCHEBI:13392 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | causally_upstream_of | C-4 methylsterol oxidase activitygomodel:RXN3O-9822 |
|
ERG25 ScerSGD:S000003292 | enables | C-4 methylsterol oxidase activitygomodel:RXN3O-9825 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | has_input | dioxygenCHEBI:15379 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | has_output | waterCHEBI:15377 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | has_input | 4beta-methylzymosterol-4alpha-carboxylateCHEBI:64925 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_output | waterCHEBI:15377 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | has_output | zymosteroneCHEBI:52386 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | has_output | 4beta-methylzymosterol-4alpha-carboxylateCHEBI:64925 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | has_input | 4beta-methylzymosterol-4-carbaldehydeCHEBI:87287 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | has_input | hydronCHEBI:15378 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | has_output | 4alpha-methylzymosterolCHEBI:1949 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | has_input | lanosterolCHEBI:16521 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | has_output | NAD(P)(+)CHEBI:13390 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | has_input | 4alpha-carboxyzymosterol(1-)CHEBI:143575 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9821 | has_input | NAD(P)HCHEBI:13392 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | has_input | 4alpha-formylzymosterolCHEBI:146131 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9826 | has_input | NAD(P)HCHEBI:13392 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-314 | has_output | NADP(3-)CHEBI:58349 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | part_of | zymosterol biosynthetic processGO:0036197 |
|
Delta14-sterol reductase activitygomodel:RXN66-306 | part_of | zymosterol biosynthetic processGO:0036197 |
|
ERG25 ScerSGD:S000003292 | enables | C-4 methylsterol oxidase activitygomodel:RXN3O-9822 |
|
Delta14-sterol reductase activitygomodel:RXN66-306 | has_output | 14-demethyllanosterolCHEBI:18364 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 | has_input | NAD(P)(+)CHEBI:13390 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | has_input | NAD(P)(+)CHEBI:13390 |
|
ERG26 ScerSGD:S000002969 | enables | 3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-318 |
|
sterol 14-demethylase activitygomodel:RXN3O-9820 | part_of | zymosterol biosynthetic processGO:0036197 |
|
Delta14-sterol reductase activitygomodel:RXN66-306 | has_input | 4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-olCHEBI:17813 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9823 | has_output | NAD(P)(+)CHEBI:13390 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | has_output | 4alpha-hydroxymethylzymosterolCHEBI:146130 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9825 | part_of | zymosterol biosynthetic processGO:0036197 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | has_output | carbon dioxideCHEBI:16526 |
|
3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activitygomodel:RXN66-313 | has_output | 3-dehydro-4alpha-methylzymosterolCHEBI:136486 |
|
Delta14-sterol reductase activitygomodel:RXN66-306 | has_input | hydronCHEBI:15378 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9822 | has_output | 4beta-methylzymosterol-4-carbaldehydeCHEBI:87287 |
|
C-4 methylsterol oxidase activitygomodel:RXN3O-9824 | has_input | NAD(P)HCHEBI:13392 |
|
3-beta-hydroxysteroid 3-dehydrogenase (NADP+) activitygomodel:RXN66-319 | has_output | zymosterolCHEBI:18252 |
|
ERG25 ScerSGD:S000003292 | located_in Physical protein location from reviewed UniProt. ECO:0000305 (PubMed:12119386); ECO:0000305 (PubMed:15716577); ECO:0000305 (PubMed:8663358) Topology: Single-pass membrane protein. | endoplasmic reticulum membraneGO:0005789 |
|
ERG11 ScerSGD:S000001049 | located_in Physical protein location from reviewed UniProt. ECO:0000305 Topology: Single-pass membrane protein. | endoplasmic reticulum membraneGO:0005789 |
|
ERG27 ScerSGD:S000004090 | located_in Physical protein location from reviewed UniProt. ECO:0000269 (PubMed:12119386); ECO:0000269 (PubMed:12842197); ECO:0000269 (PubMed:15716577) Topology: Peripheral membrane protein. | endoplasmic reticulum membraneGO:0005789 |
|
ERG27 ScerSGD:S000004090 | located_in Physical protein location from reviewed UniProt. ECO:0000269 (PubMed:12119386); ECO:0000269 (PubMed:12842197); ECO:0000269 (PubMed:15716577) | lipid dropletGO:0005811 |
|
ERG24 ScerSGD:S000005224 | located_in Physical protein location from reviewed UniProt. ECO:0000269 (PubMed:16847258) Topology: Multi-pass membrane protein. | membraneGO:0016020 |
|
ERG26 ScerSGD:S000002969 | located_in Physical protein location from reviewed UniProt. ECO:0000269 (PubMed:11279045); ECO:0000269 (PubMed:12119386); ECO:0000269 (PubMed:15716577) Topology: Peripheral membrane protein. | endoplasmic reticulum membraneGO:0005789 |
|
ERG25 ScerSGD:S000003292 | has_cofactor UniProtKB reviewed (Swiss-Prot) annotation. UniProt evidence: ECO:0000269 (PubMed:8663358) | iron cationCHEBI:24875 |
|
ERG11 ScerSGD:S000001049 | has_cofactor UniProtKB reviewed (Swiss-Prot) annotation. UniProt evidence: ECO:0000269 (PubMed:24613931) | hemeCHEBI:30413 |
|
References
gomodel:YeastPathways_PWY-6074-1GO-CAM zymosterol biosynthesis model YeastPathways_PWY-6074-1 (source version: Pinned Noctua JSON archive; model date 2024-09-12; member ./YeastPathways_PWY-6074-1.json)UniProtKB:P53045Reviewed UniProtKB P53045 location annotations (source version: UniProt release 2026_03)UniProtKB:P10614Reviewed UniProtKB P10614 location annotations (source version: UniProt release 2026_03)UniProtKB:Q12452Reviewed UniProtKB Q12452 location annotations (source version: UniProt release 2026_03)UniProtKB:P32462Reviewed UniProtKB P32462 location annotations (source version: UniProt release 2026_03)UniProtKB:P53199Reviewed UniProtKB P53199 location annotations (source version: UniProt release 2026_03)
Curation history
- Codex; review-causal-graph; Reviewed every native GO-CAM fact; preserved precise input/output, causal, location, membership and complex-part relations with traceable structured source evidence. Kept distinct generic physical instances and recorded source-scope exclusions in the cohort review ledger.
- Codex
- EDIT — Audit causal activity compartments and preserve scoped protein location evidence
Reviewed all 12 activity location assignments and 5 mapped physical proteins against reviewed S288C UniProt release2026_03 location/function/caution batch SHA256 95f72dcc644358c480e0e59f996cf88533558b5fa4256460a030e0a1eaf9678d. Added 6 independently supported location edges and quarantined 12 generic cytosol source assertions. Mapped physical protein locations via exact SGD cross-references; retained source ECO grades, molecular form and conditional notes. Physical protein location alone never generates activity location. Explicitly inspected functional assertions support bounded activity projections. Every original activity location and exclusion is recorded in reports/causal_graph_review/gocam-location-review.json. No independent location annotation is treated as an evidence gap, not a negative result. Cytoplasm is not narrowed to cytosol. Microsome fractions are not projected as in-vivo organelles. Semantic validation passed all85 records;4 independent source-role acceptance tests passed.
- EDIT — Audit causal activity compartments and preserve scoped protein location evidence