TEMPERATURE DEPENDENCY OF THERMODYNAMIC PARAMETERS IN INTERACTIONS BETWEEN HEN EGG-WHITE LYSOZYME (HEL) AND ANTI-MEL ANTIBODIES

We examined temperature dependency of thermodynamic parameters in the interactions between hen egg-white lysozyme (MEL) and anti-MEL antibod y, D1.3, and two mutant antibodies. The Delta H degrees values appeare d to decrease biphasically in the temperature range from 10 to 45 degr ees C with the apparent inflection point around 30 degrees C, The Delt a G degrees calculated from the K-A values showed only small differenc es because of entropy and enthalpy compensation. It has been argued th at large negative values of heat capacity change (Delta Cp degrees), i f observed, are mainly derived from hydrophobic interactions. However, the observed Delta Cp degrees values were too high to be ascribed onl y to hydrophobic interactions, Moreover, addition of methanol did not cause a decrease in the absolute value of Delta Cp degrees.