Back to discover

Protein / target

Amine oxidase [flavin-containing] B

Encoded byMAOBP27338Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
15
Approved medicines
Open Targets target-level
View by indication →
19
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Primary methylamine oxidase

Strongest disease association

Hypertension

Via encoding gene MAOB · Genetic evidence · score 0.07

Therapeutic position

Established drug target

Small molecules

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Catalyzes the oxidative deamination of primary and some secondary amines such as neurotransmitters, and exogenous amines including the tertiary amine, neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), with concomitant reduction of oxygen to hydrogen peroxide and participates in the met…

View complete UniProt function annotation

Catalyzes the oxidative deamination of primary and some secondary amines such as neurotransmitters, and exogenous amines including the tertiary amine, neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), with concomitant reduction of oxygen to hydrogen peroxide and participates in the metabolism of neuroactive and vasoactive amines in the central nervous system and peripheral tissues (PubMed:11049757, PubMed:11134050, PubMed:20493079, PubMed:8316221, PubMed:8665924). Preferentially degrades benzylamine and phenylethylamine (PubMed:11049757, PubMed:11134050, PubMed:20493079, PubMed:8316221, PubMed:8665924)

Subcellular location

Mitochondrion outer membrane
Domains and Gene Ontology detail (11)

Gene Ontology

  • Cmitochondrial envelope
  • Cmitochondrial outer membrane
  • Cmitochondrion
  • Felectron transfer activity
  • Fmonoamine oxidase activity
  • Fprimary methylamine oxidase activity
  • Pdopamine catabolic process
  • Phydrogen peroxide biosynthetic process
  • Pphenylethylamine catabolic process
  • Pserotonin metabolic process
  • Psubstantia nigra development

520 aa · 59 kDa · 2 isoforms

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

View underlying pathways (1)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

COMTLRTOMTDDCDBHAOC2ALDH2AOC3AOC1PRKNAOX1MAOB

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Approved medicines with mapped indications

1 medicine · 1 area

Approved therapies targeting this protein, grouped by what they are approved to treat — the disease-first view of the medicines below. Relationships come from the canonical approved-indication graph (ChEMBL phase-4), the same source as the drug cards.

Parkinson's Disease1 medicine

15 medicines meet Open Targets' target-level approved-medicine definition; the 1 shown here are those on this page with a canonical approved disease indication in the graph. Approved indications from ChEMBL (phase-4), via the canonical drug→disease graph.

Drugs targeting this protein

1

How approved and investigational drugs engage this protein — mechanism and action type, direct vs complex targeting, and how broadly each acts across other targets. A drug-first view (the section above groups the approved ones disease-first); direct binders with few recorded targets are listed first.

Selegiline
Narrow target profileApprovedInhibitor

Monoamine oxidase B inhibitor

Indicated for Parkinson's Disease

Direct interaction with this protein · Only this protein recorded as a target

ChEMBL mechanism, action type, target identity and approved indications. Open Targets clinical status.

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene MAOB

Gene-level evidence surfaced through the gene MAOB that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Parkinson's Disease
0.78Well supported

Clinical evidence dominant · Open Targets 0.63

Major depressive disorder
0.73Moderately supported

Clinical evidence dominant · Open Targets 0.59

Depressive Disorder
0.63Moderately supported

Clinical evidence dominant · Open Targets 0.50

Hypertension
0.50Limited support

Clinical evidence dominant · Open Targets 0.38

Cocaine-Related Disorders
0.36Limited support

Clinical evidence dominant · Open Targets 0.29

View evidence synthesis (5)
Parkinson's DiseaseWell supported
0.78
agreement 0.620.93
Clinical84%Literature16%

Open Targets aggregate 0.63 · 2 independent evidence families

Major depressive disorderModerately supported
0.73
agreement 0.580.89
Clinical91%Literature9%

Open Targets aggregate 0.59 · 2 independent evidence families

Depressive DisorderModerately supported
0.63
agreement 0.470.78
Clinical93%Literature7%

Open Targets aggregate 0.50 · 2 independent evidence families

HypertensionLimited support
0.50
agreement 0.390.60
Clinical85%Genetic13%Literature2%

Open Targets aggregate 0.38 · 3 independent evidence families

Cocaine-Related DisordersLimited support
0.36
agreement 0.200.52
Clinical98%Literature2%

Open Targets aggregate 0.29 · 2 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations
Parkinson's Disease0.63
Major depressive disorder0.59
Depressive Disorder0.50
Hypertension0.38
Neurodegenerative Diseases0.31
Cocaine-Related Disorders0.29
Neuralgia0.28

Drug development

18 compounds recorded · 15 approved · 1 in clinical development · 2 earlier-stage

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 1 drug that targets this protein in Forefront's canonical graph (1 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (10)
PHENELZINE SULFATEApproval
SELEGILINEApproval
MEBANAZINEUnknown
PARGYLINEApproval
PHENOXYPROPAZINEUnknown
ISOCARBOXAZIDApproval
PHENELZINEApproval
RASAGILINE MESYLATEApproval
IPRONIAZIDApproval
RALFINAMIDEPhase 3

Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.

Tractability

Small moleculesStrong

Approved Drug and Structure with Ligand support this modality.

AntibodiesEmerging

Feasibility evidence (uniprot sigp or tmhmm) — no clinical-stage drug of this modality recorded.

Protein degradersEmerging

Feasibility evidence (database ubiquitination and half-life data) — no clinical-stage drug of this modality recorded.

View underlying tractability evidence (9)
SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketSM · Druggable FamilyAB · UniProt SigP or TMHMMPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule Binder

Raw Open Targets tractability assessment buckets, by modality.

Safety-related annotations

diarrhoeaBrennan et al. (2024)hallucinationsBrennan et al. (2024)dyskinesiaBrennan et al. (2024)dizzinessBrennan et al. (2024)HypertensionBrennan et al. (2024)

Terms indexed against this target in Open Targets' safety data, with their datasource. These are annotations, not causal claims: the direction of effect (whether activation or inhibition is implicated), species and evidence strength are not captured here, so an entry does not mean that modulating this target is known to cause that condition.

Clinical trials

19

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.

View all trials (15)

COMPLETED · via Selegiline · NCT01495195

COMPLETED · via Selegiline · NCT01330030

COMPLETED · via Selegiline · NCT00218517

COMPLETED · via Selegiline · NCT00129311

COMPLETED · via Selegiline · NCT00000336

COMPLETED · via Selegiline · NCT00000188

COMPLETED · via Selegiline · NCT00000201

COMPLETED · via Selegiline · NCT00000337

ClinicalTrials.gov via the drug-target graph.

What's happening now

2

Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for a drug that targets this protein, plus publications where such a drug is a genuine subject. Every item is reached indirectly through the drug, not the protein itself; incidental mentions (a paper that merely measures a drug) and press items are excluded.

  1. New publication2010-09-01
    Failure to improve cigarette smoking abstinence with transdermal selegiline + cognitive behavior therapy.

    Addiction (Abingdon, England) · 2010 · 26 citations · Europe PMC · via Selegiline

  2. New publication1997-04-01
    A controlled trial of selegiline, alpha-tocopherol, or both as treatment for Alzheimer's disease. The Alzheimer's Disease Cooperative Study.

    The New England journal of medicine · 1997 · 1,344 citations · Europe PMC · via Selegiline

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.