SMOX: Spermine Oxidase – Key Regulator of Polyamine Metabolism
Comprehensive genomic and functional analysis of the SMOX gene, its role in polyamine catabolism, and implications in cancer and neurological disorders.
Gene Information Card
| Symbol | SMOX |
|---|---|
| Full Name | Spermine Oxidase |
| Gene Type | Protein coding |
| Chromosomal Location | 20p13 |
| NCBI Gene ID | 54498 ncbi.nlm.nih.gov/gene/54498 |
| Ensembl ID | ENSG00000101204 |
| UniProt ID | Q9NWM0 |
| OMIM ID | 615159 |
| HGNC ID | 15862 |
| Aliases | PAOh1, SMO, MGC138499 |
Description
SMOX (spermine oxidase) encodes a flavin-dependent enzyme that catalyzes the oxidation of spermine to spermidine, producing hydrogen peroxide and 3-aminopropanal. This reaction is a critical step in polyamine catabolism, regulating cellular polyamine levels and generating reactive oxygen species (ROS). SMOX is implicated in cell proliferation, apoptosis, and inflammation, and its dysregulation is associated with various cancers and neurodegenerative diseases.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Colorectal Cancer | Overexpression of SMOX leads to increased ROS production and DNA damage, promoting tumorigenesis. | PMID: 21502544 |
| Prostate Cancer | Elevated SMOX activity correlates with polyamine flux and oxidative stress, contributing to cancer progression. | PMID: 23376921 |
| Alzheimer's Disease | SMOX-mediated ROS generation may contribute to neuronal oxidative damage and amyloid-beta toxicity. | PMID: 25634563 |
| Ischemic Stroke | SMOX upregulation in ischemic brain tissue exacerbates oxidative injury. | PMID: 27021521 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | Medium |
| Kidney | 8.3 | Medium |
| Brain | 6.1 | Low |
| Colon | 15.2 | High |
| Prostate | 18.7 | High |
| Lung | 5.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 22.1 | High expression in embryonic kidney cells |
| HeLa | 14.3 | Moderate expression in cervical cancer cells |
| HCT116 | 28.5 | High expression in colorectal carcinoma cells |
| SH-SY5Y | 9.8 | Moderate expression in neuroblastoma cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1045G>A (p.Gly349Arg) | Missense | 0.01% (gnomAD) | Unknown functional impact; predicted benign by SIFT |
| c.1282C>T (p.Arg428Cys) | Missense | 0.005% (gnomAD) | Potential loss of function; reduced enzyme activity in vitro |
| c.1573A>G (p.Ile525Val) | Missense | 0.02% (gnomAD) | Likely benign; no significant effect on activity |
Mutation functional classification
Loss of Function (LOF)
Rare missense variants (e.g., p.Arg428Cys) reduce spermine oxidase activity, impairing polyamine catabolism and potentially increasing cellular polyamine levels.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported in SMOX.
Dominant Negative (DN)
No evidence for dominant-negative effects of SMOX mutations.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Polyamine metabolism (Reactome: R-HSA-351202)
• Spermine catabolism (KEGG: map00330)
Protein Summary
Spermine oxidase (SMOX) is a 555-amino acid flavoprotein that localizes to the cytoplasm and cytosol. It specifically oxidizes spermine to spermidine, generating hydrogen peroxide as a byproduct. This enzyme plays a dual role in polyamine homeostasis and redox signaling. SMOX is highly expressed in the colon and prostate, and its activity is induced by polyamines and inflammatory stimuli. Structural studies reveal a conserved FAD-binding domain and a substrate-binding pocket critical for catalysis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SMOX Knockout HEK293 Cell Line | EDJ-KQ11441 | Human | 54498 | Details Get a Quote |
| SMOX Knockout A-549 Cell Line | EDJ-KQ39709 | Human | 54498 | Details Get a Quote |
| SMOX Knockout HCT 116 Cell Line | EDJ-KQ39710 | Human | 54498 | Details Get a Quote |
| SMOX Knockout HeLa Cell Line | EDJ-KQ39711 | Human | 54498 | Details Get a Quote |
| SMOX (c.1176A>G )Point Mutation in HAP1 Cell Line | EDC03610 | Human | 54498 | Details Get a Quote |
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