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Binding of basic pancreatic trypsin inhibitor and related isoinhibitors to leukocytic elastase. Determination of thermodynamic parameters
Author(s) -
Fioretti Evandro,
Angeletti Mauro,
Cottini Maria Teresa,
Ascoli Franca
Publication year - 1989
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.300020307
Subject(s) - chemistry , solvation , elastase , ionic strength , molecule , thermodynamics , divalent , pancreatic elastase , trypsin , solvent , enzyme , crystallography , organic chemistry , physics , aqueous solution
The effect of temperature, ionic strength and solvation power of mono‐ and divalent cations on the interaction of BPTI‐like inhibitors with human leukocytic elastase has been determined. The binding process is characterized by a non‐linear dependence of the equilibrium association constant on 1/ T indicating a thermal transition at temperature values ranging between 20°C and 35°C depending on the solvent. The marked dependence of the thermodynamic parameters (ΔH°, ΔS°, ΔG°) and of the transition temperature on the concentration and nature of the cations present in solution seems to indicate that the transition, probably of conformational nature, is related to removal of water molecules upon enzyme/inhibitor complex formation.