Tmic
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Record Information
Version2.0
Creation Date2009-07-05 02:42:53 UTC
Update Date2014-12-24 20:25:41 UTC
Accession NumberT3D2553
Identification
Common Name4-Aminopyridine
ClassSmall Molecule
DescriptionDalfampridine is a potassium channel blocker used to help multiple sclerosis patients walk. This is the first drug that was specifically approved to help with mobility in these patients. FDA approved on January 22, 2010. 4-Aminopyridine is an organic compound with the formula H2NC5H4N. The molecule is one of the three isomeric amines of pyridine. 4-Aminopyridine (4-AP) is prepared by the decarbonylation of pyridine-4-carboxyamide using sodium hypochlorite via the Hofmann rearrangement (11).
Compound Type
  • Amine
  • Drug
  • Industrial Precursor/Intermediate
  • Organic Compound
  • Potassium Channel Blocker
  • Synthetic Compound
Chemical Structure
Thumb
Synonyms
Synonym
4-Aminopyridine
4-AP
4-Pyridinamine
4-Pyridylamine
Ampyra
Avitrol
Dalfampridine
EL-970
Fampridina
Fampridine
Fampridine-SR
Fampridinum
Fampyra
gamma-Aminopyridine
N07XX07
P-Aminopyridine
Chemical FormulaC5H6N2
Average Molecular Mass94.115 g/mol
Monoisotopic Mass94.053 g/mol
CAS Registry Number504-24-5
IUPAC Name1,4-dihydropyridin-4-imine
Traditional Name4-aminopyridine
SMILESN=C1C=CNC=C1
InChI IdentifierInChI=1S/C5H6N2/c6-5-1-3-7-4-2-5/h1-4H,(H2,6,7)
InChI KeyInChIKey=NUKYPUAOHBNCPY-UHFFFAOYSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as aminopyridines and derivatives. These are organic heterocyclic compounds containing an amino group attached to a pyridine ring.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassPyridines and derivatives
Sub ClassAminopyridines and derivatives
Direct ParentAminopyridines and derivatives
Alternative Parents
Substituents
  • Aminopyridine
  • Heteroaromatic compound
  • Azacycle
  • Organic nitrogen compound
  • Organopnictogen compound
  • Hydrocarbon derivative
  • Primary amine
  • Organonitrogen compound
  • Amine
  • Aromatic heteromonocyclic compound
Molecular FrameworkAromatic heteromonocyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Extracellular
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
Applications
Biological Roles
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceColourless solid (11).
Experimental Properties
PropertyValue
Melting Point157-161°C
Boiling Point273°C
Solubility74 g/L
LogPNot Available
Predicted Properties
PropertyValueSource
Water Solubility6.73 g/LALOGPS
logP-0.65ALOGPS
logP0.29ChemAxon
logS-1.1ALOGPS
pKa (Strongest Acidic)16.04ChemAxon
pKa (Strongest Basic)12.18ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area35.88 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity40.09 m³·mol⁻¹ChemAxon
Polarizability9.66 ųChemAxon
Number of Rings1ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash Key
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-0006-9000000000-d76cf775a4e0c55c9a50View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0002-9000000000-b9ca65a501bd24b8adf5View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0002-9000000000-5b9ddb3af3ab551845d8View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0v00-9000000000-68383f33699a6453bc49View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0006-9000000000-f240dc053a801a491f6cView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0006-9000000000-1b9fe497d4864ae333efView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-002f-9000000000-ea15c905b0157a6e6115View in MoNA
MSMass Spectrum (Electron Ionization)splash10-0006-9000000000-8298bac1cfd86955d1eeView in MoNA
1D NMR1H NMR SpectrumNot AvailableView in JSpectraViewer
1D NMR13C NMR SpectrumNot AvailableView in JSpectraViewer
Toxicity Profile
Route of ExposureInhalation (10, 7) ; oral (10, 7) ; dermal (10, 7) ; intravenous (10, 7) Orally-administered dalfampridine is rapidly and completely absorbed from the gastrointestinal tract. Tmax, immediate release form = 1 hour; Tmax, extended release form = 3.5 hours; Cmax, 10 mg extended release = 17.3 - 21.6 ng/mL; Relative bioavailability of 10 mg extended-release tablets compared to aqueous oral solution = 96%
Mechanism of Toxicity4-Aminopyridine blocks potassium channels and thereby increases acetylcholine, and possibly noradrenaline, release at nerve terminals (1). In MS, axons are progressively demyelinated which exposes potassium channels. As a result, there is a leak of potassium ions which results in the repolarization of cells and a decrease in neuronal excitability. The overall impact is the impairment of neuromuscular transmission as it is harder to trigger an action potential. Dalfampridine inhibits voltage-gated potassium channels in the CNS to maintain the transmembrane potential and prolong action potential. In other words, dalfampridine works to make sure that the current available is high enough to stimulate conduction in demyelinated axons that are exposed in MS patients. Furthermore, it facilitates neuromuscular and synaptic transmission by relieving conduction blocks in demyelinated axons.
MetabolismNot extensively metabolized by the liver therefore drugs effecting the cytochrome P450 enzyme system that are concomitantly administered with dalfampridine are not expected to interact with each other. 4-Aminopyridine is rapidly absorbed into the bloodstream from the gastrointestinal tract. It is readily broken down, or metabolized, in the liver into removable compounds excreted in urine. After intravenous and oral absoprtion, the metabolites were almost all excreted in the urine. It does not to concentrate or accumulate in skin. 4-Aminopyridine is excreted in urine and rapidly detoxified in the liver (9, 12). Metabolites include 3-hydroxy-4-aminopyridine and 3-hydroxy-4-aminopyridine sulfate and both are inactive. CYP2E1 is the enzyme responsible for 3-hydroxylation of dalfampridine. Route of Elimination: Almost all of the dose and its metabolites are completely eliminated by the kidneys after 24 hours. Urine (96%; 90% of total dose as unchanged drug); Feces (0.5%) Half Life: Immediate release form = 3.5 hours; Extended release form = 5.47 hours;
Toxicity ValuesLD50, oral, mouse = 19 mg/kg LD50, oral, rat = 21 mg/kg LD50: 20-29 mg/kg (Oral, Rat) (12) LD50: 3.7 mg/kg (Oral, Dog) (12) LD50: 326 mg/kg (Dermal, Rabbit) (12)
Lethal DoseNot Available
Carcinogenicity (IARC Classification)No indication of carcinogenicity to humans (not listed by IARC).
Uses/SourcesDalfampridine is a neurofunctional modifier that helps improve walking speed in patients with multiple sclerosis (MS). It is used primarily as a research tool, in characterizing subtypes of potassium channel, and has also been used to manage some of the symptoms of multiple sclerosis, for which it has orphan drug status in the United States and is undergoing Phase III clinical trials as of 2008 (11).
Minimum Risk LevelNot Available
Health EffectsConditions associated with overdose have included parasthesias, seizures, and atrial fibrillation. Human systemic effects by ingestion include hallucinations and distorted perceptions, and dyspnea (11).
SymptomsLocal irritation on contact with the skin, mucous membranes and cornea. Symptoms floowing ingestion include vomiting, Weakness, dizziness, disorientation, hyperexcitability, tremors, periorbital paresthesias and tonic-clonic seizures may be noted (8, 10, 7).
TreatmentAdminister charcoal as a slurry. Consider gastric lavage after ingestion of a potentially life-threatening amount of poison if it can be performed soon after ingestion (generally within 1 hour). Protect airway by placement in Trendelenburg and left lateral decubitus position or by endotracheal intubation. Control any seizures first. Following inhalation, move patient to fresh air and monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with inhaled beta2 agonist and oral or parenteral corticosteroids. In case of eye exposure, irrigate exposed eyes with copious amounts of room temperature water for at least 15 minutes. If the exposure occurs through dermal exposure, remove contaminated clothing and wash exposed area thoroughly with soap and water. (8)
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDDB06637
HMDB IDNot Available
PubChem Compound ID1727
ChEMBL IDCHEMBL284348
ChemSpider ID1664
KEGG IDC13728
UniProt IDNot Available
OMIM ID
ChEBI ID34385
BioCyc IDNot Available
CTD IDD015761
Stitch ID4-Aminopyridine
PDB IDNot Available
ACToR ID6358
Wikipedia Link4-Aminopyridine
References
Synthesis Reference

Fabio GARAVAGLIA, Alessandro BAROZZA, Jacopo ROLETTO, Paolo PAISSONI, “ONE-POT PROCESS FOR THE SYNTHESIS OF DALFAMPRIDINE.” U.S. Patent US20110319628, issued December 29, 2011.

MSDST3D2553.pdf
General References
  1. Soni N, Kam P: 4-aminopyridine-a review. Anaesth Intensive Care. 1982 May;10(2):120-6. [6285756 ]
  2. Panitch H, Applebee A: Treatment of walking impairment in multiple sclerosis: an unmet need for a disease-specific disability. Expert Opin Pharmacother. 2011 Jul;12(10):1511-21. doi: 10.1517/14656566.2011.586338. Epub 2011 Jun 2. [21635193 ]
  3. Pikoulas TE, Fuller MA: Dalfampridine: a medication to improve walking in patients with multiple sclerosis. Ann Pharmacother. 2012 Jul-Aug;46(7-8):1010-5. doi: 10.1345/aph.1Q714. Epub 2012 Jul 3. [22764324 ]
  4. Cornblath DR, Bienen EJ, Blight AR: The safety profile of dalfampridine extended release in multiple sclerosis clinical trials. Clin Ther. 2012 May;34(5):1056-69. doi: 10.1016/j.clinthera.2012.03.007. Epub 2012 Apr 11. [22497693 ]
  5. McDonald S, Clements JN: Dalfampridine: a new agent for symptomatic management of multiple sclerosis. Am J Health Syst Pharm. 2011 Dec 15;68(24):2335-40. doi: 10.2146/ajhp110134. [22135060 ]
  6. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
  7. Lewis RJ (1996). Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold.
  8. Rumack BH (2009). POISINDEX(R) Information System. Englewood, CO: Micromedex, Inc. CCIS Volume 141, edition expires Aug, 2009.
  9. Gosselin RE, Smith RP, and Hodge HC (1984). Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins.
  10. International Labour Office (1983). Encyclopedia of Occupational Health and Safety. Volumes. I and II. Geneva, Switzerland: International Labour Office.
  11. Wikipedia. 4-Aminopyridine. Last Updated 8 May 2009. [Link]
  12. Extension Toxicology Network (1996). Pesticide Information Profile for 4-Aminopyridine. A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis. [Link]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available

Targets

General Function:
Voltage-gated ion channel activity
Specific Function:
Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.
Gene Name:
KCNA3
Uniprot ID:
P22001
Molecular Weight:
63841.09 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
Dissociation195 uMNot AvailableBindingDB 10458
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
  2. Baell JB, Gable RW, Harvey AJ, Toovey N, Herzog T, Hansel W, Wulff H: Khellinone derivatives as blockers of the voltage-gated potassium channel Kv1.3: synthesis and immunosuppressive activity. J Med Chem. 2004 Apr 22;47(9):2326-36. [15084131 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and the central nervous system, but also in the kidney (PubMed:19903818). Contributes to the regulation of the membrane potential and nerve signaling, and prevents neuronal hyperexcitability (PubMed:17156368). Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:19912772). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, KCNA6, KCNA7, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:12077175, PubMed:17156368). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation of delayed rectifier potassium channels (PubMed:12077175, PubMed:17156368). In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Homotetrameric KCNA1 forms a delayed-rectifier potassium channel that opens in response to membrane depolarization, followed by slow spontaneous channel closure (PubMed:19912772, PubMed:19968958, PubMed:19307729, PubMed:19903818). In contrast, a heterotetrameric channel formed by KCNA1 and KCNA4 shows rapid inactivation (PubMed:17156368). Regulates neuronal excitability in hippocampus, especially in mossy fibers and medial perforant path axons, preventing neuronal hyperexcitability. Response to toxins that are selective for KCNA1, respectively for KCNA2, suggests that heteromeric potassium channels composed of both KCNA1 and KCNA2 play a role in pacemaking and regulate the output of deep cerebellar nuclear neurons (By similarity). May function as down-stream effector for G protein-coupled receptors and inhibit GABAergic inputs to basolateral amygdala neurons (By similarity). May contribute to the regulation of neurotransmitter release, such as gamma-aminobutyric acid (GABA) release (By similarity). Plays a role in regulating the generation of action potentials and preventing hyperexcitability in myelinated axons of the vagus nerve, and thereby contributes to the regulation of heart contraction (By similarity). Required for normal neuromuscular responses (PubMed:11026449, PubMed:17136396). Regulates the frequency of neuronal action potential firing in response to mechanical stimuli, and plays a role in the perception of pain caused by mechanical stimuli, but does not play a role in the perception of pain due to heat stimuli (By similarity). Required for normal responses to auditory stimuli and precise location of sound sources, but not for sound perception (By similarity). The use of toxins that block specific channels suggest that it contributes to the regulation of the axonal release of the neurotransmitter dopamine (By similarity). Required for normal postnatal brain development and normal proliferation of neuronal precursor cells in the brain (By similarity). Plays a role in the reabsorption of Mg(2+) in the distal convoluted tubules in the kidney and in magnesium ion homeostasis, probably via its effect on the membrane potential (PubMed:23903368, PubMed:19307729).
Gene Name:
KCNA1
Uniprot ID:
Q09470
Molecular Weight:
56465.01 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Intracellular cyclic nucleotide activated cation channel activity
Specific Function:
Mediates voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient. The channel activity is up-regulated by cAMP.
Gene Name:
KCNA10
Uniprot ID:
Q16322
Molecular Weight:
57784.47 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and the central nervous system, but also in the cardiovascular system. Prevents aberrant action potential firing and regulates neuronal output. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:19912772, PubMed:8495559, PubMed:11211111, PubMed:23769686). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, KCNA6, KCNA7, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:8495559, PubMed:20220134). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation of delayed rectifier potassium channels. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Homotetrameric KCNA2 forms a delayed-rectifier potassium channel that opens in response to membrane depolarization, followed by slow spontaneous channel closure (PubMed:19912772, PubMed:23769686). In contrast, a heteromultimer formed by KCNA2 and KCNA4 shows rapid inactivation (PubMed:8495559). Regulates neuronal excitability and plays a role as pacemaker in the regulation of neuronal action potentials (By similarity). KCNA2-containing channels play a presynaptic role and prevent hyperexcitability and aberrant action potential firing (By similarity). Response to toxins that are selective for KCNA2-containing potassium channels suggests that in Purkinje cells, dendritic subthreshold KCNA2-containing potassium channels prevent random spontaneous calcium spikes, suppressing dendritic hyperexcitability without hindering the generation of somatic action potentials, and thereby play an important role in motor coordination (By similarity). Plays a role in the induction of long-term potentiation of neuron excitability in the CA3 layer of the hippocampus (By similarity). May function as down-stream effector for G protein-coupled receptors and inhibit GABAergic inputs to basolateral amygdala neurons (By similarity). May contribute to the regulation of neurotransmitter release, such as gamma-aminobutyric acid (GABA) (By similarity). Contributes to the regulation of the axonal release of the neurotransmitter dopamine (By similarity). Reduced KCNA2 expression plays a role in the perception of neuropathic pain after peripheral nerve injury, but not acute pain (By similarity). Plays a role in the regulation of the time spent in non-rapid eye movement (NREM) sleep (By similarity).
Gene Name:
KCNA2
Uniprot ID:
P16389
Molecular Weight:
56716.21 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:19912772, PubMed:8495559). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:8495559). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Homotetrameric KCNA4 forms a potassium channel that opens in response to membrane depolarization, followed by rapid spontaneous channel closure (PubMed:19912772, PubMed:8495559). Likewise, a heterotetrameric channel formed by KCNA1 and KCNA4 shows rapid inactivation (PubMed:17156368).
Gene Name:
KCNA4
Uniprot ID:
P22459
Molecular Weight:
73256.64 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity involved in sa node cell action potential repolarization
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane. Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:12130714). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation (PubMed:12130714). Homotetrameric channels display rapid activation and slow inactivation (PubMed:8505626, PubMed:12130714). May play a role in regulating the secretion of insulin in normal pancreatic islets. Isoform 2 exhibits a voltage-dependent recovery from inactivation and an excessive cumulative inactivation (PubMed:11524461).
Gene Name:
KCNA5
Uniprot ID:
P22460
Molecular Weight:
67227.15 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient (PubMed:2347305, PubMed:14575698). The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:2347305, PubMed:14575698). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA6, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (By similarity). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation (By similarity). Homotetrameric channels display rapid activation and slow inactivation (PubMed:2347305).
Gene Name:
KCNA6
Uniprot ID:
P17658
Molecular Weight:
58728.21 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Delayed rectifier potassium channel activity
Specific Function:
Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient (By similarity).
Gene Name:
KCNA7
Uniprot ID:
Q96RP8
Molecular Weight:
50558.415 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Ubiquitin-like protein binding
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain, but also in the pancreas and cardiovascular system. Contributes to the regulation of the action potential (AP) repolarization, duration and frequency of repetitive AP firing in neurons, muscle cells and endocrine cells and plays a role in homeostatic attenuation of electrical excitability throughout the brain (PubMed:23161216). Plays also a role in the regulation of exocytosis independently of its electrical function (By similarity). Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane. Homotetrameric channels mediate a delayed-rectifier voltage-dependent outward potassium current that display rapid activation and slow inactivation in response to membrane depolarization (PubMed:8081723, PubMed:1283219, PubMed:10484328, PubMed:12560340, PubMed:19074135, PubMed:19717558, PubMed:24901643). Can form functional homotetrameric and heterotetrameric channels that contain variable proportions of KCNB2; channel properties depend on the type of alpha subunits that are part of the channel (By similarity). Can also form functional heterotetrameric channels with other alpha subunits that are non-conducting when expressed alone, such as KCNF1, KCNG1, KCNG3, KCNG4, KCNH1, KCNH2, KCNS1, KCNS2, KCNS3 and KCNV1, creating a functionally diverse range of channel complexes (PubMed:10484328, PubMed:11852086, PubMed:12060745, PubMed:19074135, PubMed:19717558, PubMed:24901643). Heterotetrameric channel activity formed with KCNS3 show increased current amplitude with the threshold for action potential activation shifted towards more negative values in hypoxic-treated pulmonary artery smooth muscle cells (By similarity). Channel properties are also modulated by cytoplasmic ancillary beta subunits such as AMIGO1, KCNE1, KCNE2 and KCNE3, slowing activation and inactivation rate of the delayed rectifier potassium channels (By similarity). In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Major contributor to the slowly inactivating delayed-rectifier voltage-gated potassium current in neurons of the central nervous system, sympathetic ganglion neurons, neuroendocrine cells, pancreatic beta cells, cardiomyocytes and smooth muscle cells. Mediates the major part of the somatodendritic delayed-rectifier potassium current in hippocampal and cortical pyramidal neurons and sympathetic superior cervical ganglion (CGC) neurons that acts to slow down periods of firing, especially during high frequency stimulation. Plays a role in the induction of long-term potentiation (LTP) of neuron excitability in the CA3 layer of the hippocampus (By similarity). Contributes to the regulation of glucose-induced action potential amplitude and duration in pancreatic beta cells, hence limiting calcium influx and insulin secretion (PubMed:23161216). Plays a role in the regulation of resting membrane potential and contraction in hypoxia-treated pulmonary artery smooth muscle cells. May contribute to the regulation of the duration of both the action potential of cardiomyocytes and the heart ventricular repolarization QT interval. Contributes to the pronounced pro-apoptotic potassium current surge during neuronal apoptotic cell death in response to oxidative injury. May confer neuroprotection in response to hypoxia/ischemic insults by suppressing pyramidal neurons hyperexcitability in hippocampal and cortical regions (By similarity). Promotes trafficking of KCNG3, KCNH1 and KCNH2 to the cell surface membrane, presumably by forming heterotetrameric channels with these subunits (PubMed:12060745). Plays a role in the calcium-dependent recruitment and release of fusion-competent vesicles from the soma of neurons, neuroendocrine and glucose-induced pancreatic beta cells by binding key components of the fusion machinery in a pore-independent manner (By similarity).
Gene Name:
KCNB1
Uniprot ID:
Q14721
Molecular Weight:
95876.615 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Protein heterodimerization activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and smooth muscle cells. Channels open or close in response to the voltage difference across the membrane, letting potassium ions pass in accordance with their electrochemical gradient. Homotetrameric channels mediate a delayed-rectifier voltage-dependent outward potassium current that display rapid activation and slow inactivation in response to membrane depolarization. Can form functional homotetrameric and heterotetrameric channels that contain variable proportions of KCNB1; channel properties depend on the type of alpha subunits that are part of the channel. Can also form functional heterotetrameric channels with other alpha subunits that are non-conducting when expressed alone, such as KCNS1 and KCNS2, creating a functionally diverse range of channel complexes. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Contributes to the delayed-rectifier voltage-gated potassium current in cortical pyramidal neurons and smooth muscle cells.
Gene Name:
KCNB2
Uniprot ID:
Q92953
Molecular Weight:
102561.99 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient. Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNC2, and possibly other family members as well. Contributes to fire sustained trains of very brief action potentials at high frequency in pallidal neurons.
Gene Name:
KCNC1
Uniprot ID:
P48547
Molecular Weight:
57941.87 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain. Contributes to the regulation of the fast action potential repolarization and in sustained high-frequency firing in neurons of the central nervous system. Homotetramer channels mediate delayed-rectifier voltage-dependent potassium currents that activate rapidly at high-threshold voltages and inactivate slowly. Forms tetrameric channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:15709110). Can form functional homotetrameric and heterotetrameric channels that contain variable proportions of KCNC1, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel. Channel properties may be modulated either by the association with ancillary subunits, such as KCNE1, KCNE2 or KCNE3 or indirectly by nitric oxide (NO) through a cGMP- and PKG-mediated signaling cascade, slowing channel activation and deactivation of delayed rectifier potassium channels (By similarity). Contributes to fire sustained trains of very brief action potentials at high frequency in retinal ganglion cells, thalamocortical and suprachiasmatic nucleus (SCN) neurons and in hippocampal and neocortical interneurons (PubMed:15709110). Sustained maximal action potential firing frequency in inhibitory hippocampal interneurons is negatively modulated by histamine H2 receptor activation in a cAMP- and protein kinase (PKA) phosphorylation-dependent manner. Plays a role in maintaining the fidelity of synaptic transmission in neocortical GABAergic interneurons by generating action potential (AP) repolarization at nerve terminals, thus reducing spike-evoked calcium influx and GABA neurotransmitter release. Required for long-range synchronization of gamma oscillations over distance in the neocortex. Contributes to the modulation of the circadian rhythm of spontaneous action potential firing in suprachiasmatic nucleus (SCN) neurons in a light-dependent manner (By similarity).
Gene Name:
KCNC2
Uniprot ID:
Q96PR1
Molecular Weight:
70224.915 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
This protein mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.
Gene Name:
KCNC3
Uniprot ID:
Q14003
Molecular Weight:
80577.23 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Metal ion binding
Specific Function:
Pore-forming (alpha) subunit of voltage-gated rapidly inactivating A-type potassium channels. May contribute to I(To) current in heart and I(Sa) current in neurons. Channel properties are modulated by interactions with other alpha subunits and with regulatory subunits.
Gene Name:
KCND1
Uniprot ID:
Q9NSA2
Molecular Weight:
71329.6 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain. Mediates the major part of the dendritic A-type current I(SA) in brain neurons (By similarity). This current is activated at membrane potentials that are below the threshold for action potentials. It regulates neuronal excitability, prolongs the latency before the first spike in a series of action potentials, regulates the frequency of repetitive action potential firing, shortens the duration of action potentials and regulates the back-propagation of action potentials from the neuronal cell body to the dendrites. Contributes to the regulation of the circadian rhytm of action potential firing in suprachiasmatic nucleus neurons, which regulates the circadian rhythm of locomotor activity (By similarity). Functions downstream of the metabotropic glutamate receptor GRM5 and plays a role in neuronal excitability and in nociception mediated by activation of GRM5 (By similarity). Mediates the transient outward current I(to) in rodent heart left ventricle apex cells, but not in human heart, where this current is mediated by another family member. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient (PubMed:10551270, PubMed:15454437, PubMed:14695263, PubMed:14623880, PubMed:14980201, PubMed:16934482, PubMed:24811166, PubMed:24501278). The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:11507158). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCND2 and KCND3; channel properties depend on the type of pore-forming alpha subunits that are part of the channel. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes. Interaction with specific isoforms of the regulatory subunits KCNIP1, KCNIP2, KCNIP3 or KCNIP4 strongly increases expression at the cell surface and thereby increases channel activity; it modulates the kinetics of channel activation and inactivation, shifts the threshold for channel activation to more negative voltage values, shifts the threshold for inactivation to less negative voltages and accelerates recovery after inactivation (PubMed:15454437, PubMed:14623880, PubMed:14980201, PubMed:19171772, PubMed:24501278, PubMed:24811166). Likewise, interaction with DPP6 or DPP10 promotes expression at the cell membrane and regulates both channel characteristics and activity (By similarity).
Gene Name:
KCND2
Uniprot ID:
Q9NZV8
Molecular Weight:
70535.825 Da
References
  1. Goodman AD, Stone RT: Enhancing neural transmission in multiple sclerosis (4-aminopyridine therapy). Neurotherapeutics. 2013 Jan;10(1):106-10. doi: 10.1007/s13311-012-0156-3. [23184313 ]
General Function:
Metal ion binding
Specific Function:
Pore-forming (alpha) subunit of voltage-gated rapidly inactivating A-type potassium channels. May contribute to I(To) current in heart and I(Sa) current in neurons. Channel properties are modulated by interactions with other alpha subunits and with regulatory subunits.
Gene Name:
KCND3
Uniprot ID:
Q9UK17
Molecular Weight:
73450.53 Da
References
  1. Judge SI, Bever CT Jr: Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther. 2006 Jul;111(1):224-59. Epub 2006 Feb 9. [16472864 ]
General Function:
Voltage-gated potassium channel activity involved in ventricular cardiac muscle cell action potential repolarization
Specific Function:
Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel. Channel properties are modulated by cAMP and subunit assembly. Mediates the rapidly activating component of the delayed rectifying potassium current in heart (IKr). Isoforms USO have no channel activity by themself, but modulates channel characteristics by forming heterotetramers with other isoforms which are retained intracellularly and undergo ubiquitin-dependent degradation.
Gene Name:
KCNH2
Uniprot ID:
Q12809
Molecular Weight:
126653.52 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
IC504400 uMNot AvailableBindingDB 10458
References
  1. Du LP, Tsai KC, Li MY, You QD, Xia L: The pharmacophore hypotheses of I(Kr) potassium channel blockers: novel class III antiarrhythmic agents. Bioorg Med Chem Lett. 2004 Sep 20;14(18):4771-7. [15324906 ]