Seroatlas · Human Serome Atlas

SMOX

Spermine oxidase

Also known as: C20orf16, dJ779E11.1, FLJ20746, MGC1010, PAO, PAOh1, SMO, SMOX_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9NWM0
Gene
SMOX
Ensembl
ENSG00000088826
Chromosome
20
Canonical length
555 aa
Protein class
Enzymes, Metabolic proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Nuclear membrane,Vesicles,Cytosol

OverviewNCBI Gene

Polyamines are ubiquitous polycationic alkylamines which include spermine, spermidine, putrescine, and agmatine. These molecules participate in a broad range of cellular functions which include cell cycle modulation, scavenging reactive oxygen species, and the control of gene expression. These molecules also play important roles in neurotransmission through their regulation of cell-surface receptor activity, involvement in intracellular signalling pathways, and their putative roles as neurotransmitters. This gene encodes an FAD-containing enzyme that catalyzes the oxidation of spermine to spermadine and secondarily produces hydrogen peroxide. Multiple transcript variants encoding different isoenzymes have been identified for this gene, some of which have failed to demonstrate significant oxidase activity on natural polyamine substrates. The characterized isoenzymes have distinctive biochemical characteristics and substrate specificities, suggesting the existence of additional levels of complexity in polyamine catabolism. [provided by RefSeq, Jul 2012]

Canonical amino-acid sequenceUniProt

555 residues, UniProt reviewed canonical sequence.

>Q9NWM0|SMOX
     1  MQSCESSGDS ADDPLSRGLR RRGQPRVVVI GAGLAGLAAA KALLEQGFTD VTVLEASSHI
    61  GGRVQSVKLG HATFELGATW IHGSHGNPIY HLAEANGLLE ETTDGERSVG RISLYSKNGV
   121  ACYLTNHGRR IPKDVVEEFS DLYNEVYNLT QEFFRHDKPV NAESQNSVGV FTREEVRNRI
   181  RNDPDDPEAT KRLKLAMIQQ YLKVESCESS SHSMDEVSLS AFGEWTEIPG AHHIIPSGFM
   241  RVVELLAEGI PAHVIQLGKP VRCIHWDQAS ARPRGPEIEP RGEGDHNHDT GEGGQGGEEP
   301  RGGRWDEDEQ WSVVVECEDC ELIPADHVIV TVSLGVLKRQ YTSFFRPGLP TEKVAAIHRL
   361  GIGTTDKIFL EFEEPFWGPE CNSLQFVWED EAESHTLTYP PELWYRKICG FDVLYPPERY
   421  GHVLSGWICG EEALVMEKCD DEAVAEICTE MLRQFTGNPN IPKPRRILRS AWGSNPYFRG
   481  SYSYTQVGSS GADVEKLAKP LPYTESSKTA PMQVLFSGEA THRKYYSTTH GALLSGQREA
   541  ARLIEMYRDL FQQGT

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SMOX 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)
0.27
Highest tissue expression
63 nTPM

Expression across tissuesHPA

Tissue

  • midbrain: 63 nTPM
  • amygdala: 62 nTPM
  • basal ganglia: 55 nTPM
  • cerebral cortex: 51 nTPM
  • hippocampal formation: 43 nTPM
  • spinal cord: 39 nTPM

Single-cell type

  • platelets: 917 nCPM
  • epicardial cells: 162 nCPM
  • megakaryocytes: 74 nCPM
  • astrocytes: 71 nCPM
  • erythrocytes: 66 nCPM
  • esophageal apical cells: 62 nCPM

Immune cell

  • total PBMC: 16 nTPM
  • neutrophil: 3.6 nTPM
  • myeloid DC: 2.4 nTPM
  • plasmacytoid DC: 1.1 nTPM
  • classical monocyte: 1 nTPM
  • intermediate monocyte: 0.4 nTPM

Brain region

  • basal ganglia: 79 nTPM
  • medulla oblongata: 69 nTPM
  • thalamus: 69 nTPM
  • cerebellum: 65 nTPM
  • midbrain: 64 nTPM
  • white matter: 63 nTPM

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)
0.47
gnomAD pLI
0.4
gnomAD missense Z
2.26
DepMap mean gene effect
-0.01
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% 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 SMOX as an antibody target. Whether an autoantibody or antibody against SMOX could matter depends on whether native SMOX is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SMOX 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 SMOX as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SMOX. 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).

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