Carbonic Anhydrase IV

The carbonic anhydrases (or carbonate dehydratases) are classified as metalloenzyme for its zinc ion prosthetic group and form a family of enzymes that catalyze the rapid interconversion of carbon dioxide and water to bicarbonate and protons, a reversible reaction that takes part in maintaining acid-base balance in blood and other tissues. The carbonic anhydrasekl (CA) family consists of at least 11 enzymatically active members and a few inactive homologous proteins. Carbonic anhydrase IV (CAIV) is a membrane-associated enzyme anchored to plasma membrane surfaces by a phosphatidylinositol glycan linkage. CAIV is a high-activity isozyme in CO2 hydration comparable to that of CAII. Furthermore, CAIV is more active in HCO3- dehydration than is CAII. However, the esterase activity of CAIV is decreased 150-fold compared to CAII.

Carbonic Anhydrase IV Related Areas

Enzyme>>Carbonic Anhydrase>>Carbonic Anhydrase IV

Carbonic Anhydrase IV Alternative Names

Carbonic Anhydrase IV, CA-IV, CAIV, Car4, RP17 [Homo sapiens]

Carbonic Anhydrase IV, CA IV, Ca4, Car4, RP23-167D6.1, AW456718 [Mus musculus]

Summaries for Carbonic Anhydrase IV

Entrez Gene summary for Carbonic Anhydrase IV:

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 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. This gene encodes a glycosylphosphatidyl-inositol-anchored membrane isozyme expressed on the luminal surfaces of pulmonary (and certain other) capillaries and proximal renal tubules. Its exact function is not known; however, it may have a role in inherited renal abnormalities of bicarbonate transport.

OMIM - description for Carbonic Anhydrase IV:

Carbonic anhydrases (CAs) are a family of zinc metalloenzymes. For background information on the CA family, see 114800. CA IV is a glycosylphosphatidylinositol-anchored membrane isozyme expressed on the luminal surfaces of pulmonary (and certain other) capillaries and on the luminal surface of proximal renal tubules. CA IV has ancient evolutionary status among CA isozymes. It is functionally important in CO2 and bicarbonate transport and has a possible role in inherited renal abnormalities of bicarbonate transport (review by Okuyama et al., 1993). CA IV is responsible for the taste of carbonation.

Wikipedia summary for Carbonic Anhydrase IV:

The carbonic anhydrases (or carbonate dehydratases) form a family of enzymes that catalyze the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa), a reversible reaction that occurs rather slowly in the absence of a catalyst.[1] The active site of most carbonic anhydrases contains a zinc ion; they are therefore classified as metalloenzymes. One of the functions of the enzyme in animals is to interconvert carbon dioxide and bicarbonate to maintain acid-base balance in blood and other tissues, and to help transport carbon dioxide out of tissues.

Human Carbonic Anhydrase IV Protein General Information

 

• Protein names: Recommended name: Carbonic anhydrase 4
• Sequence length: 312 AA.
• Domain: Signal
• Sequence similarities: Belongs to the alpha-carbonic anhydrase family.
• Enzyme regulation: Activated by histamine, L-adrenaline, D-phenylalanine, L- and D-histidine. Inhibited by coumarins, saccharin, sulfonamide derivatives such as acetazolamide and Foscarnet (phosphonoformate trisodium salt).
• Subunit structure: Interacts with SLC4A4
• Tissue specificity: Expressed in the endothelium of the choriocapillaris in eyes (at protein level). Not expressed in the retinal epithelium at detectable levels
• Involvement in disease: Defects in CA4 are the cause of retinitis pigmentosa type 17 (RP17) [MIM:600852]. RP leads to degeneration of retinal photoreceptor cells. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. RP17 inheritance is autosomal dominant. Note=Defective acid overload removal from retina and retinal epithelium, due to mutant CA4, is responsible for photoreceptor degeneration, indicating that impaired pH homeostasis is the most likely cause underlying the RP17 phenotype

General information above from UniProt

Function for Carbonic Anhydrase IV Protein

UniProtKB:

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

Genatlas:

• glycosylphosphatidyl-inositol-anchored membrane isozyme expressed on the luminal surfaces of pulmonary, chorionic (and certain other) capillaries and of proximal renal tubules
• Carbonic Anhydrase IV reversibly hydrate CO2 in cellular ion transport and pH homeostasis
• Carbonic Anhydrase IV plays a critical role by maintaining the pH in the outer retina, which is important for the normal function of photoreceptors

Homology for human Carbonic Anhydrase IV

• homolog to rattus ca4 (70 pc)

Phenotype Information for Carbonic Anhydrase IV

• Gene/Locus: CA4, RP17
• Phenotype:

  Retinitis pigmentosa 17

Phenotype Information for Carbonic Anhydrase IV from OMIM (Online Mendelian Inheritance in Man)