Dineopentyl phosphate hydrolysis: evidence for stepwise water attack

Area of Science:

• Biochemistry
• Chemical Kinetics

Background:

• Phosphate ester hydrolysis is fundamental to numerous biological processes, including energy production and signaling.
• The precise mechanism of phosphate ester hydrolysis, especially in solution, remains a subject of debate.
• Understanding solution mechanisms is critical for evaluating proposed enzyme-catalyzed pathways.

Purpose of the Study:

• To elucidate the mechanism of phosphate diester hydrolysis in solution.
• To investigate the roles of hydroxide and water as nucleophiles.
• To assess the viability of the substrate-as-base mechanism in phosphate ester hydrolysis.

Main Methods:

• Computational mapping of free energy surfaces for nucleophilic attack on dineopentyl phosphate.
• Analysis of reaction pathways for both hydroxide and water attack on the phosphate diester anion and neutral diester.
• Comparison of computational results with existing experimental data.

Main Results:

• Accurate reproduction of experimental data using computational methods.
• Demonstration that water attack on neutral phosphate diesters follows an associative mechanism with proton transfer.
• Identification of a phosphorane intermediate in the reaction pathway.
• Validation of the substrate-as-base mechanism as a viable pathway.

Conclusions:

• The study provides a detailed mechanistic understanding of phosphate ester hydrolysis in solution.
• The findings support the substrate-as-base mechanism, offering insights into enzyme-catalyzed phosphate ester hydrolysis.
• This research has significant implications for understanding biological energy transfer and signaling pathways.