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BioAssay: AID 238607

Inhibitory constant against Zn-Cam (Methanosarcina thermophila)

The first inhibition study of the beta-class carbonic anhydrase (CA, EC 4.2.1.1) from the methanoarchaeon Methanobacterium thermoautotrophicum (Cab) with anions is reported here. Inhibition data of the alpha-class human isozymes hCA I and hCA II (cytosolic) as well as the membrane-bound isozyme hCA IV and the gamma-class enzyme from another archaeon, Methanosarcina thermophila (Cam) with a large more ..
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 Tested Compounds
 Tested Compounds
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Unspecified(17)
 
 
 Tested Substances
 Tested Substances
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Unspecified(17)
 
 
 Related BioAssays
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AID: 238607
Data Source: ChEMBL (302701)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: Literature, Extracted
BioAssay Version:
Deposit Date: 2010-05-24
Modify Date: 2014-08-23

Data Table ( Complete ):           View All Data
Target
Sequence: RecName: Full=Carbonic anhydrase; Flags: Precursor
Description ..   
Protein Family: LbH_gamma_CA
Comment ..   

Related Protein 3D Structures     More BioActivity Data..
Tested Compounds:
Description:
Title: Carbonic anhydrase inhibitors. Inhibition of the beta-class enzyme from the methanoarchaeon Methanobacterium thermoautotrophicum (Cab) with anions.

Abstract: The first inhibition study of the beta-class carbonic anhydrase (CA, EC 4.2.1.1) from the methanoarchaeon Methanobacterium thermoautotrophicum (Cab) with anions is reported here. Inhibition data of the alpha-class human isozymes hCA I and hCA II (cytosolic) as well as the membrane-bound isozyme hCA IV and the gamma-class enzyme from another archaeon, Methanosarcina thermophila (Cam) with a large number of anionic species such as halides, pseudohalides, bicarbonate, carbonate, nitrate, nitrite, hydrosulfide, bisulfite, sulfate, etc., are also provided for comparison. The best Cab anion inhibitors were thiocyanate and hydrogen sulfide, with inhibition constants in the range of 0.52-0.70 mM, whereas cyanate, iodide, carbonate, and nitrate were weaker inhibitors (Ki's in the range of 7.8-13.2 mM). Fluoride, chloride, and sulfate do not inhibit this enzyme appreciably, whereas the CA substrate bicarbonate, or other anions, such as bromide, nitrite, bisulfite, or sulfamate behave as weak inhibitors (Ki in the range of 40-45 mM). It is interesting to note that the metal poison, coordinating anions cyanide and azide are also rather weak Cab inhibitors (Ki in the range of 27-55 mM), whereas sulfamide is a very weak Cab inhibitor (Ki of 103 mM), although it strongly inhibits Cam (Ki of 70 microM). Surprisingly, phenylboronic and phenylarsonic acids, which have been investigated for the inhibition of all these CAs for the first time, showed very weak activity against the alpha-CA isozymes, but were effective Cab and Cam inhibitors. The best Cab inhibitors were just these two compounds (Ki's of 0.20-0.33 mM), whereas the best Cam inhibitor was sulfamic acid (Ki of 96 nM). These major differences of behavior between the diverse CAs investigated here toward anion inhibitors can be difficultly explained considering the convergent evolution of so diverse enzymes for the binding and turnover of small molecules such as carbon dioxide and anions.
(PMID: 15357993)
Categorized Comment - additional comments and annotations
From BioAssay Depositor:
Assay Type: Functional
Target Type: Target is a single protein chain
Assay Data Source: Scientific Literature
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

* Activity Concentration.

Data Table (Concise)
Data Table ( Complete ):     View All Data
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