Recording and Simulating Proton-Related Metabolism in Bacterial Cell Suspensions.

Area of Science:

• Microbiology
• Biochemistry
• Bioenergetics

Background:

• Metabolic activities in non-buffered cell suspensions induce proton release and uptake.
• Understanding these proton movements is crucial for elucidating energy conservation mechanisms.

Purpose of the Study:

• To develop and validate a new freeware application (proton.exe) for simulating substrate turnover rates based on proton flux.
• To analyze various proton-related metabolic activities in Desulfovibrio desulfuricans using kinetic modeling.

Main Methods:

• Measurement of proton release and uptake using a pH electrode in non-buffered cell suspensions.
• Simulation of substrate turnover rates, transmembrane ΔpH, membrane potential, and ATP gains using the proton.exe software.
• Experimental analysis of sulfate, nitrate, and nitrite reduction, and electron transport-coupled proton translocation in Desulfovibrio desulfuricans.

Main Results:

• The proton.exe software accurately simulates metabolic processes using Michaelis-Menten or first-order kinetics.
• The study determined H+/e- ratios for electron-transport driven proton translocation, yielding more realistic values than previous methods.
• Kinetic simulation parameters were verified using serial reactant additions.

Conclusions:

• The developed approach enables the study of diverse proton-related metabolic activities at micromolar concentrations and short time scales.
• The proton.exe application provides a versatile tool for quantitative analysis of microbial bioenergetics.
• This method offers a more accurate assessment of proton translocation efficiencies in bacteria.