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Baroresistant buffer mixtures for biochemical analyses
R Jason Quinlan1, Gregory D Reinhart
1Department of Biochemistry and Biophysics, Texas A&M University, Texas Agricultural Experiment Station, 2128 TAMU, College Station, TX 77843, USA.
Analytical Biochemistry
|May 4, 2005
Summary
Hydrostatic pressure affects buffer pH, crucial for biochemical studies. Creating buffer mixtures, especially with Tris and carboxylates or phosphates, significantly reduces pressure-induced pH shifts, enabling more reliable experiments.
Area of Science:
- Biochemistry
- Biophysics
- Physical Chemistry
Background:
- Hydrostatic pressure is a valuable tool in studying protein dynamics and interactions.
- Pressure-induced changes in buffer pK(a) values can significantly impact experimental outcomes.
- Cationic buffers are often preferred to minimize pH shifts, but effects can still be consequential.
Purpose of the Study:
- To systematically investigate the pressure-dependent pH effects on commonly used buffers in the neutral pH range.
- To identify buffer systems that exhibit minimal pH changes under hydrostatic pressure.
- To develop pressure-resistant buffer mixtures for biochemical applications.
Main Methods:
- Fluorescence-based assays were employed to measure pH changes.
- Systematic examination of various individual buffers and buffer mixtures under hydrostatic pressure.
- Analysis of buffer components including cationic, Good's, carboxylate, and phosphate buffers.
Main Results:
- Cationic and Good's buffers generally increase in pH by 0.1-0.3 pH units/kbar under pressure.
- Carboxylate and phosphate buffers decrease in pH by a similar magnitude.
- Buffer mixtures combining cationic and carboxylate/phosphate components showed an order of magnitude reduction in pressure sensitivity.
Conclusions:
- Buffer mixtures, particularly those containing Tris with phosphate, tricarballylate, or CDA, demonstrate significant baroresistance.
- Optimized buffer mixtures can maintain stable pH across a range of pressures (e.g., 7-8 pH).
- These pressure-resilient buffer systems are valuable for conducting reliable biochemical experiments under hydrostatic pressure.