ACE Protein

Angiotensin-Converting Enzyme (ACE) Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">ACE Protein</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Angiotensin-Converting Enzyme</td>
</tr>
<tr>
<td class="label">Gene</td>
<td>ACE</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P12821</td>
</tr>
<tr>
<td class="label">PDB Structures</td>
<td>1O86, 1UZF, 2C6N</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~170 kDa (somatic)</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Plasma membrane (type I transmembrane)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>M2 metalloprotease family</td>
</tr>
<tr>
<td class="label">Tissue</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Lung endothelium</td>
<td>High</td>
</tr>
<tr>
<td class="label">Vascular endothelium</td>
<td>High</td>
</tr>
<tr>
<td class="label">Brain ([neurons](/entities/neurons), glia)</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Testis</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Kidney</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Drug Class</td>
<td>Examples</td>
</tr>
<tr>
<td class="label">ACE inhibitors</td>
<td>Captopril, Enalapril, Lisinopril</td>
</tr>
<tr>
<td class="label">Brain-penetrant ACE inhibi

...

Angiotensin-Converting Enzyme (ACE) Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">ACE Protein</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Angiotensin-Converting Enzyme</td>
</tr>
<tr>
<td class="label">Gene</td>
<td>ACE</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P12821</td>
</tr>
<tr>
<td class="label">PDB Structures</td>
<td>1O86, 1UZF, 2C6N</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~170 kDa (somatic)</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Plasma membrane (type I transmembrane)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>M2 metalloprotease family</td>
</tr>
<tr>
<td class="label">Tissue</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Lung endothelium</td>
<td>High</td>
</tr>
<tr>
<td class="label">Vascular endothelium</td>
<td>High</td>
</tr>
<tr>
<td class="label">Brain ([neurons](/entities/neurons), glia)</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Testis</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Kidney</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Drug Class</td>
<td>Examples</td>
</tr>
<tr>
<td class="label">ACE inhibitors</td>
<td>Captopril, Enalapril, Lisinopril</td>
</tr>
<tr>
<td class="label">Brain-penetrant ACE inhibitors</td>
<td>Perindopril, Trandolapril</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">84 edges</a></td>
</tr>
</table>

Introduction

Ace Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

Angiotensin-converting enzyme (ACE) is a zinc-dependent dipeptidyl carboxypeptidase that plays a central role in the renin-angiotensin system[@riordan2001]. The protein exists in two forms: somatic ACE (found in vascular endothelium) and germinal ACE (found in testis). ACE is a major therapeutic target for cardiovascular disease and has implications in neurodegenerative diseases[@kehoe2009]. Beyond its classical role in blood pressure regulation, ACE has been increasingly recognized for its roles in neuroinflammation, synaptic function, and cognitive processes.

Protein Information

Structure

ACE is a type I transmembrane glycoprotein with:

• Extracellular domain: Contains two homologous domains (N- and C-terminal), each with a zinc-binding HEXXH motif
• Single transmembrane helix: Anchors protein to plasma membrane
• Cytoplasmic tail: Short intracellular domain

Each catalytic domain can hydrolyze substrates independently, but the N-terminal domain is the primary site for angiotensin I conversion[@bernstein2005]. The two domains share 60% sequence homology but have distinct substrate specificities.

Normal Function

ACE catalyzes two important reactions:

Angiotensin I → Angiotensin II: Conversion of inactive decapeptide to active octapeptide vasoconstrictor

Bradykinin degradation: Inactivates vasodilatory bradykinin

Key functions:

• Blood pressure regulation through angiotensin II generation
• Electrolyte and fluid balance
• Vascular remodeling and fibrosis
• Inflammatory response modulation
• Neuropeptide metabolism in the brain

Angiotensin II Signaling

ACE-generated angiotensin II acts through two receptor subtypes:

• AT1R: Mediates most classical effects (vasoconstriction, aldosterone secretion, thirst)
• AT2R: Often has opposing effects (vasodilation, natriuresis, tissue protection)

Expression Pattern

ACE exhibits tissue-specific expression:

In the brain, ACE is expressed in:

• Cerebral [cortex](/brain-regions/cortex) (pyramidal neurons)
• [Hippocampus](/brain-regions/hippocampus) (CA1-CA3 regions)
• Basal ganglia
• [Hypothalamus](/brain-regions/hypothalamus)
• Choroid plexus

Molecular Mechanisms

Catalytic Mechanism

ACE uses a zinc-dependent mechanism:
. Zinc1 ion (Zn²⁺) coordinated by three histidine residues

Water molecule activated for nucleophilic attack

Peptide bond hydrolysis

Product release

Brain-Specific Functions

In the central nervous system, ACE:

• Regulates neuronal excitability through angiotensin II
• Modulates synaptic plasticity and memory formation
• Controls neuroinflammation via [NF-κB](/entities/nf-kb) signaling
• Influences cerebral blood flow through vascular tone

Role in Disease

Alzheimer's Disease

• Elevated ACE activity in AD brains[@vardy2015]
• Angiotensin II promotes neuroinflammation through AT1R
• ACE I/D polymorphism affects AD risk and progression
• ACE inhibitors may provide neuroprotection through reduced Ang II signaling
• Studies show reduced [amyloid-beta](/proteins/amyloid-beta) pathology in ACE-inhibited mouse models
• Clinical observations suggest slower cognitive decline in ACE inhibitor users

Parkinson's Disease

• ACE polymorphisms influence PD susceptibility[@liu2017]
• Angiotensin II may affect dopaminergic neuron survival
• ACE inhibitors show potential neuroprotective effects in PD models
• The renin-angiotensin system intersects with dopamine metabolism

Stroke and Vascular Cognitive Impairment

• ACE contributes to vascular dysfunction
• ACE inhibition improves cerebral blood flow
• Reduces ischemic damage in experimental models

Amyotrophic Lateral Sclerosis (ALS)

• ACE activity elevated in ALS patients
• May contribute to excitotoxicity through bradykinin
• ACE inhibitors being explored as potential therapy

Therapeutic Targeting

Clinical Considerations

• Blood pressure effects: First-line concern in clinical use
• Cough: Most common side effect due to bradykinin accumulation
• Angioedema: Rare but serious adverse effect
• Combination therapy: Often with diuretics for enhanced effect

Research Directions

Novel Therapeutic Approaches

Selective AT2R agonists: Promote neuroprotective signaling

ACE2 activators: Increase angiotensin-(1-7) protective pathway

Dual ACE/NEP inhibitors: Enhance beneficial peptide generation

Brain-specific ACE inhibitors: Maximize CNS effects

Biomarker Potential

ACE activity is being explored as:

• Prognostic marker in AD progression
• Treatment response indicator
• Vascular dysfunction biomarker

Animal Models

Key findings from animal studies:

• ACE transgenic mice: Show increased Ang II and neuroinflammation
• ACE knockout mice: Protected from ischemic injury
• ACE inhibitor treated: Reduced amyloid pathology, improved cognition

Key Publications

^[1] Riordan JF. Angiotensin-converting enzyme: from zinc metallopeptidase. Ann N Y Acad Sci. 2001;947:67-76. PMID: 11795238(https://pubmed.ncbi.nlm.nih.gov/11795238/)

^[2] Kehoe PG, et al. Angiotensin-converting enzyme and Alzheimer's disease. Nat Rev Neurol. 2009;5(10):533-538. PMID: 19763147(https://pubmed.ncbi.nlm.nih.gov/19763147/)

^[3] Bernstein KE, et al. A modern understanding of ACE. Am J Physiol. 2005;289(4):F613-621. PMID: 16143598(https://pubmed.ncbi.nlm.nih.gov/16143598/)

^[4] Vardy ER, et al. ACE inhibitors and Alzheimer's disease. J Alzheimers Dis. 2015;45(2):377-387. PMID: 25537020(https://pubmed.ncbi.nlm.nih.gov/25537020/)

^[5] Liu H, et al. ACE I/D polymorphism and Parkinson's disease. Neurol Sci. 2017;38(5):791-796. PMID: 28271282(https://pubmed.ncbi.nlm.nih.gov/28271282/)

^[6] Jiang T, et al. Angiotensin-converting enzyme in neurodegeneration. Prog Neurobiol. 2022;208:102173. PMID: 35176482(https://pubmed.ncbi.nlm.nih.gov/35176482/)

^[7] O'Dwyer G, et al. ACE and Alzheimer's disease. J Mol Neurosci. 2010;40(1-2):211-215. PMID: 20082152(https://pubmed.ncbi.nlm.nih.gov/20082152/)

See Also

• [ACE Gene](/proteins/ace-protein)
• [Renin-Angiotensin System](/mechanisms/renin-angiotensin-system)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Neuroinflammation Pathway](/mechanisms/neuroinflammation)
• [Angiotensin II Receptor](/entities/angiotensin-receptor)

External Links

• [ACE Protein - UniProt](https://www.uniprot.org/uniprot/P12821)
• [ACE Structure - PDB](https://www.rcsb.org/structure/1O86)
• [ACE Gene - NCBI](https://www.ncbi.nlm.nih.gov/gene/1636)
• [ClinicalTrials.gov - ACE inhibitors and dementia](https://clinicaltrials.gov)

Background

The study of Ace Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

Brain Atlas Resources

• [Allen Human Brain Atlas](https://human.brain-map.org/) — protein expression data
• [Allen Cell Type Atlas](https://celltypes.brain-map.org/) — cell type specific expression
• [BrainSpan Atlas](https://brainspan.org/) — developmental transcriptome
• [Allen Mouse Brain Atlas](https://mouse.brain-map.org/) — mouse brain expression

References

[Riordan JF, Angiotensin-converting enzyme: from zinc metallopeptidase (2001)](https://pubmed.ncbi.nlm.nih.gov/11795238/)

[Kehoe PG, et al, Angiotensin-converting enzyme and Alzheimer's disease (2009)](https://pubmed.ncbi.nlm.nih.gov/19763147/)

[Bernstein KE, et al, A modern understanding of ACE (2005)](https://pubmed.ncbi.nlm.nih.gov/16143598/)

[Vardy ER, et al, ACE inhibitors and Alzheimer's disease (2015)](https://pubmed.ncbi.nlm.nih.gov/25537020/)

[Liu H, et al, ACE I/D polymorphism and Parkinson's disease (2017)](https://pubmed.ncbi.nlm.nih.gov/28271282/)

[Jiang T, et al, Angiotensin-converting enzyme in neurodegeneration (2022)](https://pubmed.ncbi.nlm.nih.gov/35176482/)

[O'Dwyer G, et al, ACE and Alzheimer's disease (2010)](https://pubmed.ncbi.nlm.nih.gov/20082152/)

Related Hypotheses

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

• [Circadian Glymphatic Entrainment via Targeted Orexin Receptor Modulation](/hypothesis/h-9e9fee95) — <span style="color:#81c784;font-weight:600">0.77</span> · Target: HCRTR1/HCRTR2
• [Endothelial Glycocalyx Regeneration via Syndecan-1 Upregulation](/hypothesis/h-fb56c8a0) — <span style="color:#81c784;font-weight:600">0.69</span> · Target: SDC1
• [Matrix Stiffness Normalization via Targeted Lysyl Oxidase Inhibition](/hypothesis/h-82922df8) — <span style="color:#81c784;font-weight:600">0.69</span> · Target: LOX/LOXL1-4
• [Astroglial Gap Junction Coordination via Connexin-43 Phosphorylation Modulation](/hypothesis/h-3a901ec3) — <span style="color:#81c784;font-weight:600">0.66</span> · Target: GJA1
• [Pericyte Contractility Reset via Selective PDGFR-β Agonism](/hypothesis/h-73e4340b) — <span style="color:#ffd54f;font-weight:600">0.56</span> · Target: PDGFRB
• [Aquaporin-4 Polarization Enhancement via TREK-1 Channel Modulation](/hypothesis/h-9eae33ba) — <span style="color:#ffd54f;font-weight:600">0.56</span> · Target: KCNK2
• [Osmotic Gradient Restoration via Selective AQP1 Enhancement in Choroid Plexus](/hypothesis/h-0dea0ed5) — <span style="color:#ffd54f;font-weight:600">0.51</span> · Target: AQP1

Related Analyses:

• [Perivascular spaces and glymphatic clearance failure in AD](/analysis/SDA-2026-04-01-gap-v2-ee5a5023) &#x1f504;
• [Extracellular vesicle biomarkers for early AD detection](/analysis/SDA-2026-04-02-gap-ev-ad-biomarkers) &#x1f504;