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BioAssay: AID 238541

Inhibition constant of anion against human carbonic anhydrase isozyme hCA II

A detailed inhibition study of five carbonic anhydrase (CA, EC 4.2.1.1) isozymes with inorganic phosphates, carbamoyl phosphate, the antiviral phosphonate foscarnet as well as formate is reported. The cytosolic isozyme hCA I was weakly inhibited by neutral phosphate, strongly inhibited by carbamoyl phosphate (K(I) of 9.4 microM), and activated by hydrogen- and dihydrogenphosphate, foscarnet and more ..
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 Tested Compounds
 Tested Compounds
All(8)
 
 
Unspecified(8)
 
 
 Tested Substances
 Tested Substances
All(8)
 
 
Unspecified(8)
 
 
 Related BioAssays
 Related BioAssays
AID: 238541
Data Source: ChEMBL (302635)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: Literature, Extracted
BioAssay Version:
Deposit Date: 2010-05-24
Modify Date: 2014-05-20

Data Table ( Complete ):           All
Target
Sequence: RecName: Full=Carbonic anhydrase 2; AltName: Full=Carbonate dehydratase II; AltName: Full=Carbonic anhydrase C; Short=CAC; AltName: Full=Carbonic anhydrase II; Short=CA-II
Description ..   
Protein Family: alpha_CA_I_II_III_XIII
Comment ..   

Gene:CA2     Related Protein 3D Structures     More BioActivity Data..
Tested Compounds:
Description:
Title: Carbonic anhydrase inhibitors. Interaction of isozymes I, II, IV, V, and IX with phosphates, carbamoyl phosphate, and the phosphonate antiviral drug foscarnet.

Abstract: A detailed inhibition study of five carbonic anhydrase (CA, EC 4.2.1.1) isozymes with inorganic phosphates, carbamoyl phosphate, the antiviral phosphonate foscarnet as well as formate is reported. The cytosolic isozyme hCA I was weakly inhibited by neutral phosphate, strongly inhibited by carbamoyl phosphate (K(I) of 9.4 microM), and activated by hydrogen- and dihydrogenphosphate, foscarnet and formate (best activator foscarnet, K(A)=12 microM). The cytosolic isozyme hCA II was weakly inhibited by all the investigated anions, with carbamoyl phosphate showing a K(I) of 0.31 mM. The membrane-associated isozyme hCA IV was the most sensitive to inhibition by phosphates/phosphonates, showing a K(I) of 84 nM for PO(4)(3-), of 9.8 microM for HPO(4)(2-), and of 9.9 microM for carbamoyl phosphate. Foscarnet was the best inhibitor of this isozyme (K(I) of 0.82 mM) highly abundant in the kidneys, which may explain some of the renal side effects of the drug. The mitochondrial isozyme hCA V was weakly inhibited by all phosphates/phosphonates, except carbamoyl phosphate, which showed a K(I) of 8.5 microM. Thus, CA V cannot be the isozyme involved in the carbamoyl phosphate synthetase I biosynthetic reaction, as hypothesized earlier. Furthermore, the relative resistance of CA V to inhibition by inorganic phosphates suggests an evolutionary adaptation of this mitochondrial isozyme to the presence of high concentrations of such anions in these energy-converting organelles, where high amounts of ATP are produced by ATP synthetase, from ADP and inorganic phosphates. The transmembrane, tumor-associated isozyme hCA IX was on the other hand slightly inhibited by all these anions.
(PMID: 15501037)
Categorized Comment
Assay Type: Binding

Assay Data Source: Scientific Literature

BAO: Assay Format: biochemical format

Target Type: Target is a single protein chain

Protein Target Class: enzyme lyase

Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
1Ki*Ki PubChem standard valueFloatμM
2Ki activity commentKi activity commentString
3Ki standard flagKi standard flagInteger
4Ki qualifierKi qualifierString
5Ki published valueKi published valueFloatmM
6Ki standard valueKi standard valueFloatnM
7Ki data validityKi data validityString
8Ki binding domainsKi binding domainsString

* Activity Concentration.

Data Table (Concise)
Classification
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