k1                               k2 Temp(oC)       t1/2(min)   Ea(kJ/mol)       ΔG(kJ/mol)   ΔH(KJ/mol)       ΔS(KJ/mol)         D     t1/2(min)  Ea(kJ/mol)      ΔG(kJ/mol)    ΔH(KJ/mol)      ΔS(KJ/mol)   D      50                4.05               2750             279.01          64.58              -214.43        27.8      4.05           2160             -339.48           -525.42         -185.94       65.8      60                2.49               2750             195.77         -18.56              -214.33        14.0      3.07           2160             -422.59           -608.56          -185.97      24.8      70                1.67               2750             112.65         -101.70            -214.35         6.1      2.93           2160              -505.7             -691.70         -186.00       21.5      80                1.34               2750             29.54           -184.84            -214.38          4.4      2.44           2160              -588.82          -774.84         -186.02       13.2                                                z-value = 7.81                                                                                                     z-value = 16.11 Experimental data collected at 50oC. The values are given as SD from triplicates. Ea is the activation energy of inactivation process. It is obtained by plotting logk1, the first order inactivation constant, against reciprocal of temperature as per the Arrhenius equation k1 is obtained from the slopes of plots of log% residual activity against time in hours. The enzymes in assay buffer were incubated at various temperatures. At regular intervals, aliquots were removed to measure the residual activity expressed relative to that of the unheated control.

Table 3: Half-life and activation parameters for the first and second phase (k1 & k2) respectively in the thermal inactivation of lipoxygenase.