NDUFA5 encodes the B13 subunit of mitochondrial Complex I (NADH:ubiquinone oxidoreductase), a critical component of the electron transport chain[@fearnley1992][@sazanov2015]. This page covers its function and role in neurodegenerative diseases.
Overview
Mermaid diagram (expand to render)
NDUFA5 (also known as B13, NUFM, UQOR13, CI-13kB) is located on chromosome 7q31.32 and encodes a 116-amino acid protein that is part of the Q module of mitochondrial Complex I["@koopman2013"]. Complex I is the largest enzyme of the mitochondrial respiratory chain, containing 45 subunits.
Function
Mitochondrial Electron Transport
NDUFA5 is essential for:
Electron transfer from NADH to ubiquinone
Proton pumping across the inner mitochondrial membrane
Maintaining Complex I assembly and stability
NADH oxidation in mitochondrial matrix
Energy Metabolism
The protein supports:
ATP production via oxidative phosphorylation
Cellular NAD+/NADH balance
Metabolic flux in high-energy tissues
ROS Regulation
Complex I is a major source of [reactive oxygen species](/entities/reactive-oxygen-species) (ROS). NDUFA5 function affects cellular oxidative stress.
Disease Associations
Parkinson's Disease
Complex I deficiency in PD substantia nigra
NDUFA5 variants associated with PD risk
Mitochondrial dysfunction in PD pathogenesis
PINK1/PARKIN mitophagy pathway links
Alzheimer's Disease
Mitochondrial dysfunction in AD brain
Complex I impairment in AD
Metabolic deficits precede pathology
Therapeutic targeting
ALS
Mitochondrial dysfunction in motor [neurons](/entities/neurons)
Complex I alterations in ALS
Energy failure in ALS pathogenesis
Leigh Syndrome
Severe childhood encephalopathy
Complex I deficiency
NDUFA5 mutations cause classic Leigh syndrome
Expression Pattern
NDUFA5 is expressed ubiquitously with highest levels in:
[Unknown, Fearnley & Walker. Conservation of components of the mitochondrial complex I (1992)](https://doi.org/10.1016/0968-0004(92)
[Unknown, Sazanov. A 3.3 Å resolution structure of human mitochondrial respiratory chain complex I: implications for the mechanism (2015)](https://doi.org/10.1016/j.bbabio.2015.11.011)
[Koopman et al, Mammalian mitochondrial complex I: biogenesis, genetics, and disease (2013)](https://doi.org/10.1136/jmedgenet-2012-101446)
Pathway Diagram
The following diagram shows the key molecular relationships involving NDUFA5 — NADH:ubiquinone Oxidoreductase Subunit A5 discovered through SciDEX knowledge graph analysis: