MAOB: Monoamine Oxidase B
Genetic and functional insights into MAOB, a key enzyme in neurotransmitter metabolism and neuropsychiatric disorders.
Gene Information Card
| Symbol | MAOB |
|---|---|
| Full Name | monoamine oxidase B |
| Gene Type | protein-coding |
| Chromosomal Location | Xp11.3 |
| NCBI Gene ID | 4129 ncbi.nlm.nih.gov/gene/4129 |
| Ensembl ID | ENSG00000069535 |
| UniProt ID | P27338 |
| OMIM ID | 309860 |
| HGNC ID | 6834 |
| Aliases | MAO-B, MGC20392 |
Description
MAOB encodes monoamine oxidase B, a mitochondrial outer membrane enzyme that catalyzes the oxidative deamination of biogenic amines, including dopamine, phenylethylamine, and benzylamine. It plays a critical role in neurotransmitter metabolism and is a target for inhibitors used in Parkinson disease and depression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Parkinson disease | Increased MAOB activity leads to elevated oxidative stress and dopamine metabolism, contributing to dopaminergic neuron loss. | PMID: 10932284; ClinVar |
| MAOB deficiency | Loss-of-function mutations reduce enzyme activity, leading to altered neurotransmitter levels and behavioral abnormalities. | OMIM 309860; PMID: 11810272 |
| Bipolar disorder | Polymorphisms in MAOB have been associated with altered monoamine metabolism and mood regulation. | PMID: 15640948; NCBI Gene |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain (cerebellum) | 12.5 | Medium |
| Brain (cortex) | 15.3 | Medium |
| Liver | 8.2 | Low |
| Kidney | 5.1 | Low |
| Heart | 2.3 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y (neuroblastoma) | 18.7 | High expression |
| HEK293 (embryonic kidney) | 3.4 | Low expression |
| HepG2 (hepatocellular carcinoma) | 6.1 | Moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.644C>T (p.Pro215Leu) | Missense | <0.01% | Reduced enzyme activity; associated with MAOB deficiency |
| c.898G>A (p.Val300Met) | Missense | 0.02% | Altered substrate specificity; reported in Parkinson disease |
| c.1246G>A (p.Gly416Ser) | Missense | <0.01% | Decreased catalytic efficiency |
Mutation functional classification
Loss of Function (LOF)
Missense mutations such as p.Pro215Leu reduce or abolish MAOB enzymatic activity, leading to impaired neurotransmitter catabolism.
Gain of Function (GOF)
No well-characterized gain-of-function mutations reported in MAOB.
Dominant Negative (DN)
No dominant-negative effects have been described for MAOB mutations.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Monoamine oxidase pathway (Reactome: R-HSA-141334)
• Dopamine degradation (KEGG: map00350)
• Tyrosine metabolism (KEGG: map00350)
Protein Summary
Monoamine oxidase B (MAOB) is a 520-amino-acid flavoenzyme localized to the mitochondrial outer membrane. It exists as a homodimer and uses FAD as a cofactor to oxidatively deaminate monoamines, producing hydrogen peroxide and aldehydes. MAOB preferentially metabolizes dopamine and phenylethylamine, and its inhibition is therapeutic in Parkinson disease and depression. The protein is highly expressed in brain and platelets.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MAOB Knockout HEK293 Cell Line | EDJ-KQ2895 | Human | 4129 | Details Get a Quote |
| MAOB Knockout HCT 116 Cell Line | EDJ-KQ23970 | Human | 4129 | Details Get a Quote |
| MAOB Knockout HeLa Cell Line | EDJ-KQ22600 | Human | 4129 | Details Get a Quote |
| MAOB Knockout A-549 Cell Line | EDJ-KQ62324 | Human | 4129 | Details Get a Quote |
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