Seroatlas · Human Serome Atlas

SPR

Sepiapterin reductase

Also known as: SDR38C1, SPRE_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
P35270
Gene
SPR
Ensembl
ENSG00000116096
Chromosome
2
Canonical length
261 aa
Protein class
Disease related genes, Enzymes, Human disease related genes, Metabolic proteins, Plasma proteins, Potential drug targets, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Cytosol
Quaternary structure
Homodimer

OverviewNCBI Gene

This gene encodes an aldo-keto reductase that catalyzes the NADPH-dependent reduction of pteridine derivatives and is important in the biosynthesis of tetrahydrobiopterin (BH4). Mutations in this gene result in DOPA-responsive dystonia due to sepiaterin reductase deficiency. A pseudogene has been identified on chromosome 1. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

261 residues, UniProt reviewed canonical sequence.

>P35270|SPR
     1  MEGGLGRAVC LLTGASRGFG RTLAPLLASL LSPGSVLVLS ARNDEALRQL EAELGAERSG
    61  LRVVRVPADL GAEAGLQQLL GALRELPRPK GLQRLLLINN AGSLGDVSKG FVDLSDSTQV
   121  NNYWALNLTS MLCLTSSVLK AFPDSPGLNR TVVNISSLCA LQPFKGWALY CAGKAARDML
   181  FQVLALEEPN VRVLNYAPGP LDTDMQQLAR ETSVDPDMRK GLQELKAKGK LVDCKVSAQK
   241  LLSLLEKDEF KSGAHVDFYD K

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPR can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.26
Highest tissue expression
99 nTPM

Expression across tissuesHPA

Tissue

  • liver: 99 nTPM
  • choroid plexus: 70 nTPM
  • pancreas: 62 nTPM
  • adrenal gland: 50 nTPM
  • kidney: 46 nTPM
  • skeletal muscle: 44 nTPM

Single-cell type

  • colonocytes: 84 nCPM
  • oocytes: 74 nCPM
  • hepatocytes: 69 nCPM
  • parietal cells: 67 nCPM
  • hofbauer cells: 67 nCPM
  • enteric transient amplifying cells: 61 nCPM

Immune cell

  • myeloid DC: 8.9 nTPM
  • classical monocyte: 8.3 nTPM
  • intermediate monocyte: 2.4 nTPM
  • total PBMC: 2.4 nTPM
  • non-classical monocyte: 0.9 nTPM
  • plasmacytoid DC: 0.9 nTPM

Brain region

  • choroid plexus: 38 nTPM
  • midbrain: 22 nTPM
  • hypothalamus: 19 nTPM
  • pons: 18 nTPM
  • medulla oblongata: 15 nTPM
  • spinal cord: 14 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about SPR.

Disease | AllUniProt

Conditions SPR is implicated in, by any mechanism.

  • Dystonia, DOPA-responsive, due to sepiapterin reductase deficiency (DRDSPRD) MIM:612716

Disease | GeneticClinVar

36 pathogenic / likely-pathogenic of 280 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.14
gnomAD pLI
0.04
gnomAD missense Z
0.73
DepMap mean gene effect
-0.09
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPR as an antibody target. Whether an autoantibody or antibody against SPR could matter depends on whether native SPR is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPR is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label SPR as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SPR. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...