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Literature summary for 7.2.2.19 extracted from
- Purification and characterization of the ouabain-sensitive H+/K+-ATPase from guinea-pig distal colon (2010), Arch. Biochem. Biophys., 496, 21-32.
Inhibitors
| Inhibitors | Comment | Organism | Structure |
|---|---|---|---|
| ATP | ATP concentrations over 5 mM induce H+/K+-ATPase activity inhibition, suggesting the existence of ATP-regulatory sites | Cavia porcellus |  |
| additional information | no inhibition by SCH-28080 and bafilomycin-A | Cavia porcellus | |
| Ouabain | - |
Cavia porcellus | |
| vanadate | - |
Cavia porcellus | |
KM Value [mM]
| KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|
| additional information | - |
additional information | kinetics at different pH, overview | Cavia porcellus | |
| 0.0245 | - |
ATP | pH 7.4, temperature not specified in the publication, with optimal concentration of ATP, Mg2+ and K+ | Cavia porcellus | |
| 0.0494 | - |
ATP | pH 7.0, temperature not specified in the publication, with optimal concentration of ATP, Mg2+ and K+ | Cavia porcellus | |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| additional information | the H+/K+-ATPase and Na+/K+-ATPase, EC 3.6.3.9, are not located at the same sub-cellular fraction. The ouabain-insensitive K+-ATPase resembles better the distribution of the Na+/K+-ATPase, suggesting that can be associated with the colonocyte basolateral plasma membrane | Cavia porcellus | - |
- |
| plasma membrane | apical not basolateral | Cavia porcellus | 5886 | - |
Metals/Ions
| Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|
| Cs+ | activates | Cavia porcellus | |
| K+ | activates, activation by K+ is independent of the accompanying anion, obtaining maximal activity at about 0.5 mM and pH 7.4, Km is 1.9 mM, not effective at pH 6.6 | Cavia porcellus | |
| Mg2+ | dependent on, optimally at 5 mM, Km is 3.4 mM or 0.5 mM with optimal ATP concentration | Cavia porcellus | |
| additional information | H+/K+-ATPase is Na+-independent, Mg2+-dependent, and activated by K+, Rb+, Cs+, and NH4 + but not by Na+, Li+, or N-methyl-glucamine | Cavia porcellus | |
| NH4+ | activates | Cavia porcellus | |
| Rb+ | activates | Cavia porcellus | |
Molecular Weight [Da]
| Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
|---|---|---|---|
| 100000 | - |
1 * 100000, alpha-subunit, + 1 * 500000, beta-subunit, alpha/beta, SDS-PAGE | Cavia porcellus |
| 500000 | - |
1 * 100000, alpha-subunit, + 1 * 500000, beta-subunit, alpha/beta, SDS-PAGE | Cavia porcellus |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| ATP + H2O + H+/in + K+/out | Cavia porcellus | - |
ADP + phosphate + H+/out + K+/in | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Cavia porcellus | - |
male guinea pigs | - |
Posttranslational Modification
| Posttranslational Modification | Comment | Organism |
|---|---|---|
| phosphoprotein | the enzyme is phosphorylated from [32P]-gamma-ATP, forming an acyl-phosphate bond, in an Mg2+-dependent, vanadate-sensitive process, and inhibited by hydroxylamine | Cavia porcellus |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| native ouabain-sensitive H+/K+-ATPase 106.5fold from isolated guinea-pig distal colon apical plasma membranes by solubilization with SDS, and discontinuous sucrose gradient centrifugation, separation from the ouabain-insensitive K+-ATPase | Cavia porcellus |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| colon | distal | Cavia porcellus | - |
| colonocyte | - |
Cavia porcellus | - |
Specific Activity [micromol/min/mg]
| Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
|---|---|---|---|
| 0.07 | - |
native ouabain-insensitive H+/K+-ATPase from colonic apical plasma membranes, pH not specified in the publication, temperature not specified in the publication | Cavia porcellus |
| 0.544 | - |
native ouabain-sensitive H+/K+-ATPase from colonic apical plasma membranes, pH not specified in the publication, temperature not specified in the publication | Cavia porcellus |
| 2.045 | - |
purified native ouabain-sensitive H+/K+-ATPase, pH not specified in the publication, temperature not specified in the publication | Cavia porcellus |
Storage Stability
| Storage Stability | Organism |
|---|---|
| -70°C, purified enzyme, loss of over 90% activity without additive, 65% activity remaining with 25% added, over 95% remaining with addtion of 10% DMSO | Cavia porcellus |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| ATP + H2O + H+/in + K+/out | - |
Cavia porcellus | ADP + phosphate + H+/out + K+/in | - |
? | |
| ATP + H2O + H+/in + K+/out | a Na+-independent, ouabain-sensitive H+/K+-exchange. K+ can be replaced by H+ in the enzyme reaction cycle, however pH-induced conformational changes cannot be discarded | Cavia porcellus | ADP + phosphate + H+/out + K+/in | - |
? | |
| CTP + H2O + H+/in + K+/out | a Na+-independent, ouabain-sensitive H+/K+-exchange, low activity with CTP | Cavia porcellus | CDP + phosphate + H+/out + K+/in | - |
? | |
| GTP + H2O + H+/in + K+/out | a Na+-independent, ouabain-sensitive H+/K+-exchange, low activity with GTP | Cavia porcellus | GDP + phosphate + H+/out + K+/in | - |
? | |
| ITP + H2O + H+/in + K+/out | a Na+-independent, ouabain-sensitive H+/K+-exchange, low activity with ITP | Cavia porcellus | IDP + phosphate + H+/out + K+/in | - |
? | |
| additional information | the enzyme is phosphorylated from [32P]-gamma-ATP, forming an acyl-phosphate bond, in an Mg2+-dependent, vanadate-sensitive process | Cavia porcellus | ? | - |
? | |
| UTP + H2O + H+/in + K+/out | a Na+-independent, ouabain-sensitive H+/K+-exchange, low activity with UTP | Cavia porcellus | UDP + phosphate + H+/out + K+/in | - |
? | |
Subunits
| Subunits | Comment | Organism |
|---|---|---|
| dimer | 1 * 100000, alpha-subunit, + 1 * 500000, beta-subunit, alpha/beta, SDS-PAGE | Cavia porcellus |
| More | H+/K+-ATPase is an alpha/beta-heterodimer, whose subunits, identified by Tandem-mass spectrometry, seem to correspond to HKalpha2 and Na+/K+-ATPase beta1-subunit, respectively | Cavia porcellus |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| H+/K+-ATPase | - |
Cavia porcellus |
| ouabain-sensitive H+/K+-ATPase | - |
Cavia porcellus |
pH Optimum
| pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
|---|---|---|---|
| 6.6 | 7.4 | the optimal pH for the ouabain-sensitive ATPase activity in the presence of K+ is pH 7.4, while the optimum pH for this activity, in the absence of K+, is pH 6.6 | Cavia porcellus |
IC50 Value
| IC50 Value | IC50 Value Maximum | Comment | Organism | Inhibitor | Structure |
|---|---|---|---|---|---|
| 0.0016 | - |
pH 7.4, temperature not specified in the publication | Cavia porcellus | vanadate | |
| 0.0017 | - |
pH 7.4, temperature not specified in the publication | Cavia porcellus | Ouabain | |
General Information
| General Information | Comment | Organism |
|---|---|---|
| physiological function | distal colon absorbs K+ through a Na+-independent, ouabain-sensitive H+/K+-exchange, associated to an apical ouabain-sensitive H+/K+-ATPase | Cavia porcellus |
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