Table 3 Thermostability parameters of VPR_ΔC and its proline variants.

Variant	T_{m (CD)} (°C)	T_{m (DSC)} (°C)	ΔH_cal (kJ/mol)	T_50% (°C)	E_{act (inactivation)} (kJ/mol)	t_{1/2 (60} _°C₎ (min)
VPR_∆C	61.9 ± 0.4	63.9 ± 0.3	528 ± 35	53.8 ± 0.4	218 ± 9	7 ± 1
VPR_∆C_N3P	64.8 ± 0.1	66.8 ± 0.3	533 ± 33	56.6 ± 0.3	203 ± 12	14 ± 1
VPR_∆C_I5P	65.1 ± 0.2	65.7 ± 0.5	570 ± 11	56.1 ± 0.2	199 ± 14	13 ± 1
VPR_∆C_N238P	60.7 ± 0.1	63.6 ± 0.2	556 ± 8	52.3 ± 0.2	209 ± 17	5 ± 1
VPR_∆C_T265P	61.6 ± 0.2	64.5 ± 0.2	451 ± 51	54.3 ± 0.2	206 ± 4	8 ± 1
VPR_∆C_N3P/I5P	67.8 ± 0.3	72.0 ± 0.8	646 ± 38	60.3 ± 0.4	208 ± 8	33 ± 3
VPR_∆C_N3P/I5P/N238P	68.8 ± 0.2	72.0 ± 0.4	679 ± 37	60.9 ± 0.5	207 ± 27	38 ± 5
VPR_∆C_N3P/I5P/T265P	69.2 ± 0.2	73.6 ± 0.3	697 ± 49	62.2 ± 0.6	194 ± 27	48 ± 7
VPR_∆C_N3P/I5P/N238P/T265P	72.1 ± 0.3	77.2 ± 0.2	683 ± 16	61.6 ± 0.6	182 ± 29	39 ± 3

Parameters shown are T_{m (CD)} the melting point of PMSF inhibited enzymes as measured by CD, T_{m (DSC)} the apparent melting point of PMSF inhibited enzymes defined as the highest peak of DSC thermograms, ΔH_cal the excess calorimetric heat released during unfolding, T_50% the temperature where half of the activity has been lost over 30 min, E_{act (inactivation)} calculated form the slope of Arrhenius graphs used to calculate T_50% and t_1/2 at 60 °C calculated form the same Arrhenius graphs. Values are expressed as the averages and the standard deviations of the mean.

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