High pressure enzyme kinetics of dextransucrase

Area of Science:

• Biochemistry
• Enzyme kinetics
• Protein denaturation

Background:

• Enzymatic reactions are sensitive to environmental conditions, including pressure.
• Understanding enzyme-substrate complex behavior under pressure is crucial for enzyme function.
• Dextran formation is catalyzed by enzymes and its pressure dependence is not fully understood.

Purpose of the Study:

• To investigate the pressure dependence of enzymatic dextran formation.
• To differentiate between thermodynamic effects and denaturation effects on enzyme activity.
• To determine the stability of the enzyme-substrate complex under varying pressures.

Main Methods:

• Enzymatic dextran formation was studied at various substrate concentrations up to 1000 atm.
• Kinetic analysis was employed to separate thermodynamic effects from first-order denaturation effects.
• Volume changes associated with complex formation and activation were calculated.

Main Results:

• First-order denaturation effects were successfully separated from thermodynamic effects.
• Thermodynamic effects indicated a volume change of 30.4–44.0 ccm/mol for formation and -13.6 ccm/mol for activation.
• Enzyme denaturation was found to be dependent on substrate concentration.

Conclusions:

• The enzyme-substrate (ES) complex is stable under the studied pressure conditions.
• Only the free enzyme undergoes denaturation, and this process is influenced by substrate concentration.
• These findings clarify the pressure-induced behavior of enzymes involved in dextran formation.