Aggregation of Phosphates Enhances Enzyme Activity in Aqueous Solution.

Area of Science:

• Physical Chemistry
• Biochemistry
• Solution Chemistry

Background:

• Understanding the behavior of phosphate salts in aqueous solutions is crucial for various chemical and biological processes.
• The influence of cations like tetrabutylammonium ([NBu4]+) and anions like dihydrogen phosphate ([H2PO4]-) on solution properties needs further investigation.
• Adenosine phosphates (ATP, ADP, AMP) play vital roles in biological systems, and their aggregation behavior in solution can impact their function.

Purpose of the Study:

• To determine the diffusion coefficients and viscosities of various phosphate salts in aqueous solutions.
• To investigate the aggregation behavior of dihydrogen phosphate and adenosine phosphates at millimolar concentrations.
• To explore the effect of increasing adenosine triphosphate (ATP) and adenosine diphosphate (ADP) concentrations on enzyme activity.

Main Methods:

• Measurements of diffusion coefficients and viscosities were conducted for tetrabutylammonium dihydrogen phosphate, potassium dihydrogen phosphate, tetrabutylammonium bromide, tetrabutylammonium chloride, adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) in aqueous solutions.
• Concentration-dependent studies were performed across millimolar concentrations.
• Enzyme activity assays were conducted using cytochrome c, laccase, and horseradish peroxidase in the presence of varying ATP and ADP concentrations.

Main Results:

• The tetrabutylammonium ([NBu4]+) cation was found to significantly increase solution viscosity at high millimolar concentrations.
• No significant aggregation of the dihydrogen phosphate ([H2PO4]-) anion was observed.
• ATP, ADP, and AMP exhibited aggregation in aqueous solutions at higher millimolar concentrations.
• The activity of cytochrome c, laccase, and horseradish peroxidase increased with increasing concentrations of ATP and ADP.

Conclusions:

• Tetrabutylammonium cations contribute to solution viscosity, while adenosine phosphates aggregate at higher concentrations.
• The observed aggregation of adenosine phosphates may influence their interactions and functions in biological systems.
• Increased concentrations of ATP and ADP enhance the activity of specific enzymes, suggesting a role in modulating biochemical pathways.