Carbonic anhydrase hydrates carbon dioxide (cytosol)

Stable Identifier
Reaction [transition]
Homo sapiens
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Carbonic anhydrase I (CA1, Khalifah 1971, Simonsson et al. 1982, Ren and Lindskog 1992), carbonic anyhydrase II (CA2, Tibell et al. 1984, Jones and Shaw 1983, Pesando 1975, Ghannam et al. 1986), carbonic anhydrase III (CA3, Carter et al. 1979, Tu et al. 1990, Tu et al. 1994, Tu et al. 1998, Silverman et al. 1993), carbonic anhydrase VII (CA7, Bootorabi et al. 2010, Gitto et al. 2010) hydrate carbon dioxide to yield bicarbonate and a proton. Carbonic anhydrase deprotonates water to yield a zinc-hydroxyl group and a proton which is transferred to external buffer molecules via histidine or glutamate residues in carbonic anhydrase. The hydroxyl group reacts with carbon dioxide in the active site to yield bicarbonate. A water molecule displaces the bicarbonate and the reaction cycle begins again (reviewed in Lindskog 1997). Depending on the concentrations of reactants the reaction is reversible.
CA2 and CA7 have high catalytic activity, CA1 has low activity (10% of the activity of CA2), and CA3 has very low activity (1% of the activity of CA2). CA1 and CA2 are found in erythrocytes. CA2 is also found in kidney, lung, and white muscle where it facilitates diffusion of carbon dioxide. CA3 is found in red muscle where it participates in resistance against oxidative stress.

Literature References
PubMed ID Title Journal Year
21282642 Intramolecular proton shuttle supports not only catalytic but also noncatalytic function of carbonic anhydrase II

Becker, HM, Klier, M, Schüler, C, McKenna, R, Deitmer, JW

Proc Natl Acad Sci U S A 2011
9336012 Structure and mechanism of carbonic anhydrase

Lindskog, S

Pharmacol Ther 1997
8083199 Interactions of active-site residues and catalytic activity of human carbonic anhydrase III

Tu, C, Chen, X, Ren, X, LoGrasso, PV, Jewell, DA, Laipis, PJ, Silverman, DN

J Biol Chem 1994
20493921 Analysis of a shortened form of human carbonic anhydrase VII expressed in vitro compared to the full-length enzyme

Bootorabi, F, Jänis, J, Smith, E, Waheed, A, Kukkurainen, S, Hytönen, V, Valjakka, J, Supuran, CT, Vullo, D, Sly, WS, Parkkila, S

Biochimie 2010
22001224 Structure and catalysis by carbonic anhydrase II: role of active-site tryptophan 5

Mikulski, R, Domsic, JF, Ling, G, Tu, C, Robbins, AH, Silverman, DN, McKenna, R

Arch Biochem Biophys 2011
4994926 The carbon dioxide hydration activity of carbonic anhydrase. I. Stop-flow kinetic studies on the native human isoenzymes B and C

Khalifah, RG

J Biol Chem 1971
6433979 Anion inhibition of CO2 hydration catalyzed by human carbonic anhydrase II. Mechanistic implications

Tibell, L, Forsman, C, Simonsson, I, Lindskog, S

Biochim Biophys Acta 1984
1554744 Buffer dependence of CO2 hydration catalyzed by human carbonic anhydrase I

Ren, X, Lindskog, S

Biochim Biophys Acta 1992
6407977 A chemical and enzymological comparison of the common major human erythrocyte carbonic anhydrase II, its minor component, and a new genetic variant, CA II Melbourne (237 Pro leads to His)

Jones, GL, Shaw, DC

Hum Genet 1983
2169869 Buffer enhancement of proton transfer in catalysis by human carbonic anhydrase III

Tu, CK, Paranawithana, SR, Jewell, DA, Tanhauser, SM, LoGrasso, PV, Wynns, GC, Laipis, PJ, Silverman, DN

Biochemistry 1990
20349499 Identification of potent and selective human carbonic anhydrase VII (hCA VII) inhibitors

Gitto, R, Agnello, S, Ferro, S, Vullo, D, Supuran, CT, Chimirri, A

ChemMedChem 2010
3080418 Activation parameters for the carbonic anhydrase II-catalyzed hydration of CO2

Ghannam, AF, Tsen, W, Rowlett, RS

J Biol Chem 1986
120192 Characterization of human carbonic anhydrase III from skeletal muscle

Carter, N, Jeffery, S, Shiels, A, Edwards, Y, Tipler, T, Hopkinson, DA

Biochem Genet 1979
20578724 Structural and kinetic study of the extended active site for proton transfer in human carbonic anhydrase II

Domsic, JF, Williams, W, Fisher, SZ, Tu, C, Agbandje-McKenna, M, Silverman, DN, McKenna, R

Biochemistry 2010
17427958 Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III

Elder, I, Fisher, Z, Laipis, PJ, Tu, C, McKenna, R, Silverman, DN

Proteins 2007
234739 Proton magnetic resonance studies of carbonic anhydrase. II. Group controlling catalytic activity

Pesando, JM

Biochemistry 1975
8399223 Rate-equilibria relationships in intramolecular proton transfer in human carbonic anhydrase III

Silverman, DN, Tu, C, Chen, X, Tanhauser, SM, Kresge, AJ, Laipis, PJ

Biochemistry 1993
6819139 A 13C nuclear magnetic resonance study of CO2/HCO-3 exchange catalyzed by human carbonic anhydrase I

Simonsson, I, Jonsson, BH, Lindskog, S

Eur J Biochem 1982
9635771 Properties of intramolecular proton transfer in carbonic anhydrase III

Tu, C, Qian, M, Earnhardt, JN, Laipis, PJ, Silverman, DN

Biophys J 1998
Event Information
Catalyst Activity

carbonate dehydratase activity of CA1,2,3,7,13:Zinc [cytosol]

Orthologous Events
Cross References
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