The enhancement of electrostriction caused by lowering the solvent dielectric constant leads to the decrease of activation energy in trypsin catalysis

H. Park, Min Chi Young Min Chi

    Research output: Contribution to journalArticlepeer-review

    6 Citations (Scopus)

    Abstract

    The contribution of electrostriction of the solvent to the stabilization of the negatively charged tetrahedral transition state of a trypsin-catalyzed reaction was probed by means of kinetic studies involving high-pressure and solvent dielectric constant. A good correlation was observed between the increased catalytic efficiency of trypsin and the decreased solvent dielectric constant. When the dielectric constant of the solvents was lowered by 4.68 units, the loss of activation energy and that of free energy of activation were 2.26 kJ/mol and 3.09 kJ/mol, respectively. The activation volume for kcat decreased significantly as the dielectric constant of the solvent decreased, indicating that the degree of electrostriction of the solvent around the charged tetrahedral transition state has been enhanced. These observations demonstrate that the increase in the catalytic efficiency of the trypsin reaction with decreasing dielectric constant resulted from the stabilization of electrostatic energy for the formation of an oxyanion hole, and this stabilization was caused by the increase of electrostricted water around the charged tetrahedral transition state. Therefore, we conclude that control of the solvent dielectric constant can stabilize the tetrahedral transition state, and this lowers the activation energy.

    Original languageEnglish
    Pages (from-to)53-59
    Number of pages7
    JournalBiochimica et Biophysica Acta - General Subjects
    Volume1568
    Issue number1
    DOIs
    Publication statusPublished - 2001 Nov 7

    Keywords

    • Activation volume
    • Dielectric constant
    • Electrostriction
    • High-pressure kinetics
    • Tetrahedral transition state
    • Trypsin

    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Molecular Biology

    Fingerprint

    Dive into the research topics of 'The enhancement of electrostriction caused by lowering the solvent dielectric constant leads to the decrease of activation energy in trypsin catalysis'. Together they form a unique fingerprint.

    Cite this