CA1 (gene)

Last updated
CA1
Protein CA1 PDB 1azm.png
Available structures
PDB Ortholog search: PDBe RCSB
Identifiers
Aliases CA1 , CA-I, CAB, Car1, HEL-S-11, carbonic anhydrase 1
External IDs OMIM: 114800 MGI: 88268 HomoloGene: 20414 GeneCards: CA1
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001083957
NM_009799

RefSeq (protein)

NP_001077426
NP_033929

Location (UCSC) Chr 8: 85.33 – 85.38 Mb Chr 3: 14.83 – 14.87 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Carbonic anhydrase 1 is an enzyme that in humans is encoded by the CA1 gene. [5] [6]

Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including cellular respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid.

They show extensive diversity in tissue distribution and in their subcellular localization. CA1 is closely linked to CA2 and CA3 genes on chromosome 8, and it encodes a cytosolic protein which is found at the highest level in erythrocytes. Transcript variants of CA1 utilizing alternative polyA_sites have been described in literature. [6]

Structure

The human CA1 protein contains an N-terminus active site, zinc binding site, and substrate-binding site. [7] The crystal structure of the human CA1-bicarbonate anion complex reveals the geometry of two H-bonds between the Glu106-Thr199 pair and the Glu117-His119 pair, and one pi H-bond between a water molecule and the phenyl ring of the Tyr114 residue. The product inhibition of CA1 via bicarbonate anions is correlated to the proton localization change on His119. So the Glu117-His119 H-bond is considered to regulate the ionicity of the zinc ion and the binding strength of the bicarbonate anion. [8]

Mechanism

The reaction catalyzed by CA1 is the same as other carbonic anhydrase family proteins:

(in tissues - high CO2 concentration) [9]

The CA1-catalyzed reaction has a relatively low reaction affinity (Km) of 4.0 mM for CO2, [7] [10] turnover number (Kcat) of 2×105 s−1, and catalytic efficiency (Kcat/Km) of 5×107 M−1s−1 comparing to other isozymes of the α-CA family of carbonic anhydrases. The turnover rate and catalytic rate of CA1 are only about 10% that of CA2 (Kcat: 1.4×106 s−1, Kcat/Km: 1.5×108 M−1s−1). [11]

Function

Carbonic anhydrase 1 belongs to α-CA sub-family and is localized in the cytosol of red blood cell, GI tract, cardiac tissues and other organs or tissues. [12] Transmembrane transport of CA-produced bicarbonate contributes significantly to cellular pH regulation. [13]

In a human zinc-activated variant of CA1, the Michigan Variant, a single point mutation changes His 67 to Arg in a critical region of the active site. This variant of the zinc metalloenzyme appears to be unique in that it possesses esterase activity that is specifically enhanced by added free zinc ions. [14]

Clinical significance

CA1 activation is associated with worsened pathological remodeling in human ischemic diabetic cardiomyopathy. [12] In diabetic mellitus type 2 patients with postinfarct heart failure who were undergoing surgical coronary revascularization, myocardial levels of CA1 were sixfold higher than nondiabetic patients. Elevated CA1 expression was mainly localized in the cardiac interstitium and endothelial cells. Furthermore, high glucose-induced elevation of CA1 hampers endothelial cell permeability and determines endothelial cell apoptosis in vitro . [12]

CA1 also mediates hemorrhagic retinal and cerebral vascular permeability through prekallikrein activation and serine protease factor XIIa generation. These phenomena induce proliferative diabetic retinopathy and diabetic macular edema disease progression, which represent leading causes of vision loss. [15]

As CA1 is an important therapeutic target, development of its inhibitors will contribute to disease treatment. Compared to other CA family members, CA1 has relatively low affinity to common CA inhibitors. [16] Nonetheless, it has medium affinity for CA inhibitor sulfonamides.[ citation needed ]

Interactions

CA1 has been shown to interact with:

These interactions have been confirmed using the high throughput method (one hit)

Related Research Articles

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Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek erythros 'red' and kytos 'hollow vessel', with -cyte translated as 'cell' in modern usage), are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O2) to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries.

<span class="mw-page-title-main">Acetazolamide</span> Chemical compound

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<span class="mw-page-title-main">Band 3 anion transport protein</span> Mammalian protein found in Homo sapiens

Band 3 anion transport protein, also known as anion exchanger 1 (AE1) or band 3 or solute carrier family 4 member 1 (SLC4A1), is a protein that is encoded by the SLC4A1 gene in humans.

<span class="mw-page-title-main">Carbonic anhydrase II</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase II, is one of sixteen forms of human α carbonic anhydrases. Carbonic anhydrase catalyzes reversible hydration of carbon dioxide. Defects in this enzyme are associated with osteopetrosis and renal tubular acidosis. Renal carbonic anhydrase allows the reabsorption of bicarbonate ions in the proximal tubule. Loss of carbonic anhydrase activity in bones impairs the ability of osteoclasts to promote bone resorption, leading to osteopetrosis.

<span class="mw-page-title-main">Carbonic anhydrase 9</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase IX is an enzyme that in humans is encoded by the CA9 gene. It is one of the 14 carbonic anhydrase isoforms found in humans and is a transmembrane dimeric metalloenzyme with an extracellular active site that facilitates acid secretion in the gastrointestinal tract. CA IX is overexpressed in many types of cancer including clear cell renal cell carcinoma (RCC) as well as carcinomas of the cervix, breast and lung where it promotes tumor growth by enhancing tumor acidosis.

<span class="mw-page-title-main">Electrogenic sodium bicarbonate cotransporter 1</span> Protein-coding gene in the species Homo sapiens

Electrogenic sodium bicarbonate cotransporter 1, sodium bicarbonate cotransporter is a membrane transport protein that in humans is encoded by the SLC4A4 gene.

<span class="mw-page-title-main">Anion exchange protein 2</span> Protein-coding gene in the species Homo sapiens

Anion exchange protein 2 (AE2) is a membrane transport protein that in humans is encoded by the SLC4A2 gene. AE2 is functionally similar to the Band 3 Cl/HCO3 exchange protein.

<span class="mw-page-title-main">Carbonic anhydrase 4</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase 4 is an enzyme that in humans is encoded by the CA4 gene.

<span class="mw-page-title-main">Carbonic anhydrase 12</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase 12 is an enzyme that in humans is encoded by the CA12 gene.

<span class="mw-page-title-main">Anion exchange protein 3</span> Protein-coding gene in the species Homo sapiens

Anion exchange protein 3 is a membrane transport protein that in humans is encoded by the SLC4A3 gene. AE3 is functionally similar to the Band 3 Cl/HCO3 exchange protein but it is expressed primarily in brain neurons and in the heart. Like AE2 its activity is sensitive to pH. AE3 mutations have been linked to seizures.

<span class="mw-page-title-main">CA10</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase-related protein 10 is an enzyme that in humans is encoded by the CA10 gene.

<span class="mw-page-title-main">CA8</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase-related protein is a protein that in humans is encoded by the CA8 gene. The CA8 protein lacks the catalytic activity of other carbonic anhydrase enzymes. A rare, autosomal recessive form of cerebellar ataxia known as "cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3" (CAMRQ3) is caused by mutations in the CA8 gene.

<span class="mw-page-title-main">Carbonic anhydrase 14</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase 14 is an enzyme that in humans is encoded by the CA14 gene.

<span class="mw-page-title-main">Carbonic anhydrase 5B, mitochondrial</span> Protein-coding gene in humans

Carbonic anhydrase 5B, mitochondrial is an enzyme that in humans is encoded by the CA5B gene.

<span class="mw-page-title-main">Carbonic anhydrase 7</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase 7 (CA7) is an enzyme that in humans is encoded by the CA7 gene.

<span class="mw-page-title-main">CA11</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase-related protein 11 is a protein that in humans is encoded by the CA11 gene.

<span class="mw-page-title-main">Carbonic anhydrase</span> Class of enzymes

The carbonic anhydrases form a family of enzymes that catalyze the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid. The active site of most carbonic anhydrases contains a zinc ion. They are therefore classified as metalloenzymes. The enzyme maintains acid-base balance and helps transport carbon dioxide.

<span class="mw-page-title-main">Carbonic anhydrase 13</span> Human protein

Carbonic anhydrase 13 is a protein that in humans is encoded by the CA13 gene.

<span class="mw-page-title-main">Carbonic anhydrase 5A, mitochondrial</span> Protein-coding gene in the species Homo sapiens

Carbonic anhydrase 5A, mitochondrial is a protein that in humans is encoded by the CA5A gene.

Carbonyl sulfide hydrolase (EC 3.13.1.7; abbreviated as COSase) is an enzyme that degrades carbonyl sulfide (COS) to hydrogen sulfide (H2S) and carbon dioxide (CO2). Isolated from Thiobacillus thioparus bacterium, the potential of COSase would reduce the high global warming effect of COS and change the ozone chemistry, because COS is the source of sulfur in the troposphere.

References

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  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000027556 - Ensembl, May 2017
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  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
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  7. 1 2 "CA1 - Carbonic anhydrase 1 - Homo sapiens (Human) - CA1 gene & protein". www.uniprot.org. Retrieved 2016-03-23.
  8. Kumar V, Kannan KK (Aug 1994). "Enzyme-substrate interactions. Structure of human carbonic anhydrase I complexed with bicarbonate". Journal of Molecular Biology. 241 (2): 226–32. doi:10.1006/jmbi.1994.1491. PMID   8057362.
  9. Carbonic acid has a pKa of around 6.36 (the exact value depends on the medium) so at pH 7 a small percentage of the bicarbonate is protonated. See carbonic acid for details concerning the equilibria HCO
    3
    + H+ H2CO3 and H2CO3 CO2 + H2O
  10. Briganti F, Mangani S, Scozzafava A, Vernaglione G, Supuran CT (Oct 1999). "Carbonic anhydrase catalyzes cyanamide hydration to urea: is it mimicking the physiological reaction?". Journal of Biological Inorganic Chemistry. 4 (5): 528–36. doi:10.1007/s007750050375. PMID   10550681. S2CID   25890428.
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Further reading