Skip to content

Reference

Evidence

CompoundsSubstances with curated findings
OutcomesMeasured endpoints
ProteinsTransporters and enzymes
InteractionsPairs that share biology
PapersEvery paper a finding cites
ArticlesReadings of the evidence

Chemistry

ReactionsRhea and Human-GEM, by subsystem
ReachWhat a compound can become

Reference layer

PathwaysReactions grouped under one name
ProcessesWhat proteins are annotated as doing
AnatomyTissues, by what is expressed there
Cell typesCells, by what is expressed there
OrganismsSpecies a compound is prepared from
MaterialsSubstances that are not one molecule
AssessmentsRegulatory determinations, transcribed
DiseasesFeatures, genes, and where each sits

Atlas Graph Twin Access

Search the graph

Reference

Evidence

Compounds
Outcomes
Proteins
Interactions
Papers
Articles

Chemistry

Reactions
Reach

Reference layer

Pathways
Processes
Anatomy
Cell types
Organisms
Materials
Assessments
Diseases

Atlas Graph Twin Access

Loading the page.

Catalyst

Computational infrastructure for human biology, built on a provenance-aware knowledge graph. Findings retain their sources; research and simulation are the next layers.

The graph

Compounds
Outcomes
Proteins
Atlas
Interactions
Papers
Articles
Graph
Search

Reference layer

Pathways
Processes
Anatomy
Cell types
Organisms
Materials
Assessments
Diseases
Reactions
Reach

How it works

Mission
Method
Twin
How to read the evidence
Sources and licences

Build on it

Access
In your assistant
For agents
Query the graph
Bulk export

A reference for what the literature reports. Not medical advice.

© 2026 CatalystPrivacy TermsReference data under the licences listed on the attribution page.

Proteins/UNIPROT:Q9H8P0

SRD5A3

Protein·UNIPROT:Q9H8P0Polyprenal reductase1 compound

Open in the graph

Plays a key role in early steps of protein N-linked glycosylation by being involved in the conversion of polyprenol into dolichol. Acts as a polyprenal reductase that mediates the reduction of polyprenal into dolichal in a NADP-dependent mechanism. Dolichols are required for the synthesis of dolichol-linked monosaccharides and the oligosaccharide precursor used for N-glycosylation. Also able to convert testosterone (T) into 5-alpha-dihydrotestosterone (DHT)..

Function from UniProtKB (Q9H8P0), read 2026-09-23. CC BY 4.0.

Curated compounds routed: 1 · substrate of

Inferred

Assembled routes, not reported.

What routes through it

1 compound

1 compound.

0 reported routes1 assembled route

testosteroneCompoundCHEBI:17347Inferred only54 paths18 endpoints

What the reference databases state

GenCC submitters' classifications

1 row

SRD5A3-congenital disorder of glycosylation has a germline basis in SRD5A3DiseaseGenCC HGNC:25812|MONDO:0012885Inferred only

Statements

32 statements

32 statements · 5 reference databases · Subject: SRD5A3 · Sources: Hetionet, Human-GEM, Reactome, Rhea, WikiPathways

Search this listOrder

SRD5A3 covaries with N4BP2ProteinHetionet hetionet:covaries:55728-79644Inferred only
SRD5A3 covaries with ZNF181ProteinHetionet hetionet:covaries:339318-79644Inferred only
SRD5A3 covaries with ZNF580ProteinHetionet hetionet:covaries:51157-79644Inferred only
ADK interacts with SRD5A3ProteinHetionet hetionet:interacts:132-79644Inferred only
NUDT15 interacts with SRD5A3ProteinHetionet hetionet:interacts:55270-79644Inferred only
SRD5A3 participates in Androgen biosynthesisPathwayReactome R-HSA-193048Inferred only
SRD5A3 participates in Asparagine N-linked glycosylationPathwayReactome R-HSA-446203Inferred only
SRD5A3 participates in Biosynthesis of the N-glycan precursor (dolichol lipid-linked oligosaccharide, LLO) and transfer to a nascent proteinPathwayReactome R-HSA-446193Inferred only
SRD5A3 participates in Defective SRD5A3 causes SRD5A3-CDG, KHRZPathwayReactome R-HSA-4755579Inferred only
SRD5A3 participates in DiseasePathwayReactome R-HSA-1643685Inferred only
SRD5A3 participates in Diseases associated with glycosylation precursor biosynthesisPathwayReactome R-HSA-5609975Inferred only
SRD5A3 participates in Diseases of glycosylationPathwayReactome R-HSA-3781865Inferred only

Show the remaining 20

SRD5A3 participates in Diseases of metabolismPathwayReactome R-HSA-5668914Inferred only
SRD5A3 participates in Glycosylation and related congenital defectsPathwayWikiPathways WP4521Inferred only
SRD5A3 participates in MetabolismPathwayReactome R-HSA-1430728Inferred only
SRD5A3 participates in Metabolism of lipidsPathwayReactome R-HSA-556833Inferred only
SRD5A3 participates in Metabolism of proteinsPathwayReactome R-HSA-392499Inferred only
SRD5A3 participates in Metabolism of steroid hormonesPathwayReactome R-HSA-196071Inferred only
SRD5A3 participates in Metabolism of steroidsPathwayReactome R-HSA-8957322Inferred only
SRD5A3 participates in N glycan biosynthesisPathwayWikiPathways WP5153Inferred only
SRD5A3 participates in Post-translational protein modificationPathwayReactome R-HSA-597592Inferred only
SRD5A3 participates in Synthesis of dolichyl-phosphatePathwayReactome R-HSA-446199Inferred only
SRD5A3 participates in Synthesis of substrates in N-glycan biosythesisPathwayReactome R-HSA-446219Inferred only
5alpha-androstan-3,17-dione is a substrate of SRD5A3CompoundHuman-GEM MAR02015Inferred only
5alpha-androstan-3,17-dione is a substrate of SRD5A3CompoundRhea RHEA:50816Inferred only
5alpha-pregnane-3,20-dione is a substrate of SRD5A3CompoundHuman-GEM MAR02002Inferred only
androst-4-ene-3,17-dione is a substrate of SRD5A3CompoundHuman-GEM MAR02015Inferred only
androst-4-ene-3,17-dione is a substrate of SRD5A3CompoundRhea RHEA:50816Inferred only
progesterone is a substrate of SRD5A3CompoundHuman-GEM MAR02002Inferred only
testosterone is a substrate of SRD5A3CompoundHuman-GEM MAR01977Inferred only
testosterone is a substrate of SRD5A3CompoundRhea RHEA:50820Inferred only
testosterone is a substrate of SRD5A3CompoundHuman-GEM MAR01976Inferred only

Reactions

8 reactions

proton+NADPH(4-)+testosterone17beta-hydroxy-5alpha-androstan-3-one+NADP(3-)
Catalysed by SRD5A3 or SRD5A1 or SRD5A2
Reaction pageLeft to rightBalancedEC 1.3.1.22cytosol
Human-GEM MAR01976CC BY 4.0Reference data
proton+NADPH(4-)+testosterone17beta-hydroxy-5alpha-androstan-3-one

Other names

6 names

Resolves to: SRD5A3

Also called: 3-oxo-5-alpha-steroid 4-dehydrogenase 3S5AR 3SR type 3SRD5A2LSteroid 5-alpha-reductase 2-likeSteroid 5-alpha-reductase 3

← Every protein Find it in the graph →

+

Catalysed by SRD5A3 or SRD5A1 or SRD5A2

Reaction pageLeft to rightBalancedEC 1.3.1.22endoplasmic reticulum

Human-GEM MAR01977CC BY 4.0Reference data

5alpha-pregnane-3,20-dione+NADP(3-)proton+NADPH(4-)+progesterone

Catalysed by SRD5A3 or SRD5A1 or SRD5A2

Reaction pageReversibleBalancedEC 1.3.1.22cytosol

Human-GEM MAR02002CC BY 4.0Reference data

androst-4-ene-3,17-dione+proton+NADPH(4-)5alpha-androstan-3,17-dione+NADP(3-)

Catalysed by SRD5A3 or SRD5A1 or SRD5A2

Reaction pageReversibleBalancedEC 1.3.1.22endoplasmic reticulum

Human-GEM MAR02015CC BY 4.0Reference data

androst-4-ene-3,17-dione+NADPH(4-)+hydron5alpha-androstan-3,17-dione+NADP(3-)

Catalysed by SRD5A1 or SRD5A3

Reaction pageReversibleBalanced

Rhea RHEA:50816CC BY 4.0Reference data

17beta-hydroxy-5alpha-androstan-3-one+NADP(3-)testosterone+NADPH(4-)+hydron

Catalysed by SRD5A1 or SRD5A2 or SRD5A3

Reaction pageRight to leftBalanced

Rhea RHEA:50820CC BY 4.0Reference data

CHEBI:13601+NADP(3-)CHEBI:47909+NADPH(4-)+hydron

Catalysed by SRD5A1 or SRD5A2 or SRD5A3

Reaction pageRight to leftBalance undeterminable

Rhea RHEA:54384CC BY 4.0Reference data

a di-trans,poly-cis-dolichal+NADP(3-)a di-trans,poly-cis-polyprenal+NADPH(4-)+hydron

Catalysed by SRD5A3

Reaction pageRight to leftBalance undeterminable

Rhea RHEA:80727CC BY 4.0Reference data