FRCD

General Function:

Zinc ion binding

Specific Function:

Reversible hydration of carbon dioxide. May stimulate the sodium/bicarbonate transporter activity of SLC4A4 that acts in pH homeostasis. It is essential for acid overload removal from the retina and retina epithelium, and acid release in the choriocapillaris in the choroid.

Gene Name:

CA4

Uniprot ID:

P22748

Molecular Weight:

35032.075 Da

Mechanism of Action:

The precise mechanism of action of topiramate is not known. However, studies have shown that topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel blocking action. Topiramate also augments the activity of the neurotransmitter gamma-aminobutyrate (GABA) at some subtypes of the GABA_A receptor (controls an integral chloride channel), indicating a possible mechanism through potentiation of the activity of GABA. Topiramate also demonstrates antagonism of the AMPA/kainate subtype of the glutamat excitatory amino acid receptor. It also inhibits carbonic anhydrase (particularly isozymes II and IV), but this action is weak and unlikely to be related to its anticonvulsant actions.

References

1. Abbate F, Casini A, Owa T, Scozzafava A, Supuran CT: Carbonic anhydrase inhibitors: E7070, a sulfonamide anticancer agent, potently inhibits cytosolic isozymes I and II, and transmembrane, tumor-associated isozyme IX. Bioorg Med Chem Lett. 2004 Jan 5;14(1):217-23. [14684331 ]

General Function:

Voltage-gated cation channel activity

Specific Function:

Ionotropic glutamate receptor. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and thereby converts the chemical signal to an electrical impulse. The receptor then desensitizes rapidly and enters a transient inactive state, characterized by the presence of bound agonist. May be involved in the transmission of light information from the retina to the hypothalamus.

Gene Name:

GRIK1

Uniprot ID:

P39086

Molecular Weight:

103979.665 Da

Mechanism of Action:

The precise mechanism of action of topiramate is not known. However, studies have shown that topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel blocking action. Topiramate also augments the activity of the neurotransmitter gamma-aminobutyrate (GABA) at some subtypes of the GABA_A receptor (controls an integral chloride channel), indicating a possible mechanism through potentiation of the activity of GABA. Topiramate also demonstrates antagonism of the AMPA/kainate subtype of the glutamat excitatory amino acid receptor. It also inhibits carbonic anhydrase (particularly isozymes II and IV), but this action is weak and unlikely to be related to its anticonvulsant actions.

References

1. Rogawski MA, Gryder D, Castaneda D, Yonekawa W, Banks MK, Lia H: GluR5 kainate receptors, seizures, and the amygdala. Ann N Y Acad Sci. 2003 Apr;985:150-62. [12724156 ]

General Function:

Zinc ion binding

Specific Function:

Reversible hydration of carbon dioxide. Can hydrates cyanamide to urea.

Gene Name:

CA1

Uniprot ID:

P00915

Molecular Weight:

28870.0 Da

References

1. Abbate F, Coetzee A, Casini A, Ciattini S, Scozzafava A, Supuran CT: Carbonic anhydrase inhibitors: X-ray crystallographic structure of the adduct of human isozyme II with the antipsychotic drug sulpiride. Bioorg Med Chem Lett. 2004 Jan 19;14(2):337-41. [14698154 ]

General Function:

Zinc ion binding

Specific Function:

Reversible hydration of carbon dioxide.

Gene Name:

CA3

Uniprot ID:

P07451

Molecular Weight:

29557.215 Da

References

1. Nishimori I, Minakuchi T, Onishi S, Vullo D, Cecchi A, Scozzafava A, Supuran CT: Carbonic anhydrase inhibitors: cloning, characterization, and inhibition studies of the cytosolic isozyme III with sulfonamides. Bioorg Med Chem. 2007 Dec 1;15(23):7229-36. Epub 2007 Aug 25. [17826101 ]

General Function:

Zinc ion binding

Specific Function:

Reversible hydration of carbon dioxide. Low activity.

Gene Name:

CA5A

Uniprot ID:

P35218

Molecular Weight:

34750.21 Da

References

1. Vitale RM, Pedone C, Amodeo P, Antel J, Wurl M, Scozzafava A, Supuran CT, De Simone G: Molecular modeling study for the binding of zonisamide and topiramate to the human mitochondrial carbonic anhydrase isoform VA. Bioorg Med Chem. 2007 Jun 15;15(12):4152-8. Epub 2007 Mar 30. [17420132 ]

Uniprot ID:

P14867; P47869; P34903; P48169; P31644; Q16445; P18505; P47870; P28472; O14764; P78334; Q8N1C3; P18507; Q99928; O00591; Q9UN88

General Function:

Zinc ion binding

Specific Function:

Essential for bone resorption and osteoclast differentiation (By similarity). Reversible hydration of carbon dioxide. Can hydrate cyanamide to urea. Involved in the regulation of fluid secretion into the anterior chamber of the eye. Contributes to intracellular pH regulation in the duodenal upper villous epithelium during proton-coupled peptide absorption. Stimulates the chloride-bicarbonate exchange activity of SLC26A6.

Gene Name:

CA2

Uniprot ID:

P00918

Molecular Weight:

29245.895 Da

Mechanism of Action:

The precise mechanism of action of topiramate is not known. However, studies have shown that topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel blocking action. Topiramate also augments the activity of the neurotransmitter gamma-aminobutyrate (GABA) at some subtypes of the GABA_A receptor (controls an integral chloride channel), indicating a possible mechanism through potentiation of the activity of GABA. Topiramate also demonstrates antagonism of the AMPA/kainate subtype of the glutamat excitatory amino acid receptor. It also inhibits carbonic anhydrase (particularly isozymes II and IV), but this action is weak and unlikely to be related to its anticonvulsant actions.

References

1. Maryanoff BE, McComsey DF, Costanzo MJ, Hochman C, Smith-Swintosky V, Shank RP: Comparison of sulfamate and sulfamide groups for the inhibition of carbonic anhydrase-II by using topiramate as a structural platform. J Med Chem. 2005 Mar 24;48(6):1941-7. [15771438 ]

General Function:

Voltage-gated sodium channel activity

Specific Function:

Mediates the voltage-dependent sodium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a sodium-selective channel through which Na(+) ions may pass in accordance with their electrochemical gradient.

Gene Name:

SCN1A

Uniprot ID:

P35498

Molecular Weight:

228969.49 Da

Mechanism of Action:

The precise mechanism of action of topiramate is not known. However, studies have shown that topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel blocking action. Topiramate also augments the activity of the neurotransmitter gamma-aminobutyrate (GABA) at some subtypes of the GABA_A receptor (controls an integral chloride channel), indicating a possible mechanism through potentiation of the activity of GABA. Topiramate also demonstrates antagonism of the AMPA/kainate subtype of the glutamat excitatory amino acid receptor. It also inhibits carbonic anhydrase (particularly isozymes II and IV), but this action is weak and unlikely to be related to its anticonvulsant actions.

References

1. Coppola G, Capovilla G, Montagnini A, Romeo A, Spano M, Tortorella G, Veggiotti P, Viri M, Pascotto A: Topiramate as add-on drug in severe myoclonic epilepsy in infancy: an Italian multicenter open trial. Epilepsy Res. 2002 Mar;49(1):45-8. [11948006 ]

General Function:

Inhibitory extracellular ligand-gated ion channel activity

Specific Function:

Component of the heteropentameric receptor for GABA, the major inhibitory neurotransmitter in the vertebrate brain. Functions also as histamine receptor and mediates cellular responses to histamine. Functions as receptor for diazepines and various anesthetics, such as pentobarbital; these are bound at a separate allosteric effector binding site. Functions as ligand-gated chloride channel (By similarity).

Gene Name:

GABRA1

Uniprot ID:

P14867

Molecular Weight:

51801.395 Da

Mechanism of Action:

The precise mechanism of action of topiramate is not known. However, studies have shown that topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel blocking action. Topiramate also augments the activity of the neurotransmitter gamma-aminobutyrate (GABA) at some subtypes of the GABA_A receptor (controls an integral chloride channel), indicating a possible mechanism through potentiation of the activity of GABA. Topiramate also demonstrates antagonism of the AMPA/kainate subtype of the glutamat excitatory amino acid receptor. It also inhibits carbonic anhydrase (particularly isozymes II and IV), but this action is weak and unlikely to be related to its anticonvulsant actions.

References

1. Overington JP, Al-Lazikani B, Hopkins AL: How many drug targets are there? Nat Rev Drug Discov. 2006 Dec;5(12):993-6. [17139284 ]