Mathematical modelling of kinetics of adenosine 5'-triphosphate hydrolysis catalyzed by Zn2+ ion in the pH range 7.1-7.4
| Autor: | Boris V. Lidskii, Militza G. Neihaus, Emma Z. Utyanskaya, Alexander E. Shilov |
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| Rok vydání: | 2000 |
| Předmět: |
Hydrolysis constant
Adenosine monophosphate Stereochemistry Hydrolysis Hydrogen Bonding Hydrogen-Ion Concentration Biochemistry Catalysis Inorganic Chemistry Adenosine Diphosphate chemistry.chemical_compound Adenosine diphosphate Acid catalysis Kinetics Zinc Adenosine Triphosphate chemistry Models Chemical ATP hydrolysis Adenosine triphosphate Equilibrium constant Mathematics |
| Zdroj: | Journal of inorganic biochemistry. 81(4) |
| ISSN: | 0162-0134 |
| Popis: | The kinetics of adenosine-5’-triphosphate (ATP) hydrolysis catalyzed by Zn2+ at pH 8.5–9.0 is analyzed by numerical simulation. The rates of product formation (adenosine diphosphate (ADP) and adenosine monophosphate (AMP)) are determined by a conformational transformation. In the sequence of steps of mutual transformations of cyclic (Cy) pH-dependent species, which are active in ATP hydrolysis to ADP, and open (Op) species, the rate-limiting step is the slow isomerization of ZnATP2-complexes. This slow step is determined by the abstraction of the OH- group from a pentacovalent intermediate catalyzed by H3O+. In the Op species,Zn 2+ is bound to the phosphate chain. In the Cy species, which can be hydrolized to ADP, Zn2+ coordinates a nitrogen atom in position 7 and γ-phosphate. The mutual transformations of conformers occur via pentacovalent intermediates with the participation of γ-phosphorus and include pseudotransformations. In the direct transformation CyOH-⦚r OpOH-, pseudotransformation is a rate-controlling step. The deprotonated open monomeric form OpOH- is inactive in hydrolysis. Within the framework of the dimeric model and a more complex model that accounts for the role of trimeric associates ZnATP2-, the general scheme of intermediate transformations is considered that accounts for the existence of a pH-independent pathway of hydrolysis. The rate and equilibrium constants are estimated. Concentration profiles for intermediate products during hydrolysis are described. |
| Databáze: | OpenAIRE |
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