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Updated: Jan 23, 2026
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Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue
Published on: June 21, 2018
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Osmolytes modify protein dynamics and function of tetrameric lactate dehydrogenase upon pressurization
Samy R Al-Ayoubi1, Paul Hendrik Schummel, Aline Cisse
1Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany. roland.winter@tu-dortmund.de.
Physical Chemistry Chemical Physics : PCCP
|June 6, 2019
Summary
Natural compounds like TMAO and glycine stabilize lactate dehydrogenase (LDH) activity under high pressure by modulating its dissociation and substrate affinity. This suggests cellular conditions can maintain enzyme function in extreme environments.
Area of Science:
- Biochemistry
- Biophysics
- Enzyme kinetics
Background:
- Enzymes function within specific cellular environments.
- Understanding how enzymes respond to physical factors like pressure is crucial.
- Natural osmolytes are known to stabilize protein structures.
Purpose of the Study:
- To investigate the combined effects of pressure and natural osmolytes (TMAO, glycine, urea) on lactate dehydrogenase (LDH) activity.
- To determine how these factors influence enzyme stability, dynamics, and catalytic efficiency.
- To explore the implications for enzyme function in extreme environments.
Main Methods:
- High-pressure stopped-flow methodology with UV/Vis spectroscopy.
- Fourier-transform infrared (FTIR) spectroscopy.
- Neutron scattering measurements.
Main Results:
- Lactate dehydrogenase (LDH) activity (kcat) increased up to 1000 bar, with dissociation into dimers occurring at this pressure.
- A negative activation volume (ΔV‡ = -45.3 mL mol⁻¹) and a larger volume for the enzyme-substrate complex were observed.
- TMAO and glycine enhanced enzyme stability and substrate affinity (lower KM), while urea had minimal effect on KM.
- Changes in fast internal dynamics did not explain the increased kcat under pressure.
Conclusions:
- Natural osmolytes modulate the pressure-induced deactivation of LDH.
- TMAO and glycine enhance substrate binding affinity, likely due to altered water-mediated interactions.
- Cellular conditions can maintain enzymatic activity across a wide range of pressures found on Earth.
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