PNPO
Pyridoxamine 5'-Phosphate Oxidase
Gene Information Card
| Symbol | PNPO |
|---|---|
| Full Name | Pyridoxamine 5'-Phosphate Oxidase |
| Gene Type | Protein coding |
| Chromosomal Location | 17q21.32 |
| NCBI Gene ID | 55163 ncbi.nlm.nih.gov/gene/55163 |
| Ensembl ID | ENSG00000108439 |
| UniProt ID | Q9BYN0 |
| OMIM ID | 603287 |
| HGNC ID | 9176 |
| Aliases | PDXPO, PNPO_HUMAN |
Description
The PNPO gene encodes pyridoxamine 5'-phosphate oxidase, a key enzyme in vitamin B6 metabolism. It catalyzes the oxidation of pyridoxamine 5'-phosphate and pyridoxine 5'-phosphate to pyridoxal 5'-phosphate (PLP), the active form of vitamin B6. PLP is an essential cofactor for numerous enzymes involved in neurotransmitter synthesis, amino acid metabolism, and other cellular processes. Mutations in PNPO cause autosomal recessive pyridoxamine 5'-phosphate oxidase deficiency, leading to neonatal epileptic encephalopathy responsive to pyridoxal phosphate.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Pyridoxamine 5'-phosphate oxidase deficiency | Loss-of-function mutations reduce PLP synthesis, impairing neurotransmitter metabolism and causing seizures | ClinVar, OMIM |
| Neonatal epileptic encephalopathy | Deficient PLP leads to reduced GABA and serotonin synthesis, resulting in early-onset seizures | OMIM, PubMed |
| Hypophosphatasia (secondary association) | Altered PLP metabolism may contribute to bone mineralization defects in some cases | PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | Medium |
| Brain | 8.3 | Medium |
| Kidney | 7.1 | Medium |
| Heart | 5.9 | Low |
| Skeletal muscle | 4.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 10.1 | Hepatocyte cell line |
| SH-SY5Y | 7.8 | Neuroblastoma cell line |
| HEK293 | 6.5 | Embryonic kidney cell line |
| K562 | 3.2 | Leukemia cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.674G>A (p.Arg225Gln) | Missense | ~30% in deficiency cases | Reduced enzyme activity |
| c.347C>T (p.Pro116Leu) | Missense | ~15% | Impaired PLP binding |
| c.98T>C (p.Leu33Pro) | Missense | ~10% | Loss of function |
| c.1A>G (p.Met1Val) | Start loss | Rare | No protein synthesis |
Mutation functional classification
Loss of Function (LOF)
Most PNPO mutations are loss-of-function, reducing or abolishing enzyme activity, leading to PLP deficiency.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • pyridoxamine-phosphate oxidase activity | • pyridoxal 5'-phosphate binding |
| • vitamin B6 metabolic process | • cellular response to vitamin B6 |
| • oxidation-reduction process |
Pathways
• Vitamin B6 metabolism
• Pyridoxal phosphate salvage pathway
Protein Summary
Pyridoxamine 5'-phosphate oxidase is a homodimeric enzyme localized in the cytoplasm. It converts pyridoxamine 5'-phosphate and pyridoxine 5'-phosphate to pyridoxal 5'-phosphate (PLP), the active cofactor form of vitamin B6. The enzyme requires FMN as a cofactor. Deficiency leads to accumulation of upstream metabolites and reduced PLP levels, causing severe neurological symptoms in infancy.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PNPO Knockout HEK293 Cell Line | EDJ-KQ2678 | Human | 55163 | Details Get a Quote |
| PNPO Knockout A-549 Cell Line | EDJ-KQ23472 | Human | 55163 | Details Get a Quote |
| PNPO Knockout HCT 116 Cell Line | EDJ-KQ23473 | Human | 55163 | Details Get a Quote |
| PNPO Knockout HeLa Cell Line | EDJ-KQ23474 | Human | 55163 | Details Get a Quote |
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