Table 2. Enthalpy and Heat Capacity Changes - Molar Values
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W. Pfeil, Protein Stability and Folding Supplement 1 © Springer-Verlag Berlin Heidelberg 2001
Acylphosphatase
285
Abrin Abrin II, type II ribosome-inactivating protein from Abrus precatorius pH
To.,
~Ht",
To.2
~H'''2
Appr.lRem.
Ref
abrin: 4.50 5.43 5.80 6.43 6.83 7.20 7.82 8.30 9.16 10.16
67.6 65.3 61.2 54.2 51.0 46.0 44.0 41.6 38.4 36.6
1356 1230 1125 1067 937 854 736 586 561 456
70.1 66.9 63.3 57.9 55.2 51.4 50.6 47.8 44.8 43.2
946 854 816 766 686 573 527 519 452 410
DSC DSC DSC DSC DSC DSC DSC DSC DSC DSC
99KI8 99KI8 99KI8 99K18 99KI8 99KI8 99K18 99KI8 99KI8 99KI8
49.7 49.0
494 506
DSC (1,2,5) DSC (1,2,5)
abrin A-subunit: 4.50 7.20
(1-4) (1-4) (1-4) (1-4) (1-4) (1-4) (1-4) (1-4) (1-4) (1-4)
99KI8 99KI8
Remarks: (1) results of deconvolution (2) buffers: 50 mM sodium acetate (pH 4.5-5.8),50 mM sodium phosphate (pH 6.4-7.9), 50 mM sodium borate (pH 8.3-9.2), 50 mM sodium carbonate (pH 10.16) (3) ~Cp from ~H'" versus To, amounts to 27±2 and 20±1 kJ/mol/K for the lower- and higher-temperature transition, respectively (4) Ref. 99K18 contains further data obtained in the presence oflactose and NaCI (5) measured in the presence of 5 mM 2-mercaptoethanol
Acylphosphatase Recombinant muscle acylphosphatase, thermodynamic parameters obtained at different urea concentrations urea conc.
pH
To.
~Cp
~H
Approach/Remarks
0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 0.0 0.0
5.50 5.50 5.50 5.50 5.50 5.50 5.50 5.50 5.50 5.50
56.5 54.6 52.6 50.7 48.2 45.4 43.1 40.0
6.15 6.07 6.28 6.19 5.86 6.19 6.20 5.77 6.15±0.60 6.61±0.70
351 335 324 305 286 276 256 238
heat heat heat heat heat heat heat heat heat heat
Remarks: (1) transition monitored by CD at 222 nm (2) measured in 50 mM acetate buffer with urea (3) experimental error 0.5°C for To.' 5% for ~H, and 10% for ~Cp (4) ~Cp in the absence of urea, extrapolated value (5) this value is considered as the best one, and was used in further calculations in Ref. 98C5 (6) ~Cp from ~HvH versus To. after taking into account the urea-protein interaction
(1-3) (1-3) (1-3) (1-3) (1-3) (1-3) (1-3) (1-3) (4,5) (6)
Ref 98C5 98C5 98C5 98C5 98C5 98C5 98C5 98C5 98C5 98C5
286
Table 2. Enthalpy and Heat Capacity Changes - Molar Values
Recombinant muscle acylphosphatase, wild type and lysine to glutamine mutants Mutant
pH
T,~
~H
Approach/Remarks
wild type
5.5 5.5 5.5 5.5 5.5 5.5
56.5 52.2 50.1 56.4 50.6 55.1
391 392 370 358 324 370
heat heat heat heat heat heat
Lys32~Gln Lys57~Gln Lys67~Gln Lys84~Gln Lys88~Gln
(1-3) (1-3) (1-3) (1-3) (1-3) (1-3)
Ref 98C6 98C6 98C6 98C6 98C6 98C6
Remarks: (1) transition monitored by CD at 222 nm (2) buffer: 50 mM acetate (3) the mean errors in Ttr, are ±1°C, and in ~H within ±1O% Common-type acylphosphatase (CT AcP) and muscle acylphosphatase (M AcP) Protein
pH
CTAcP MAcP
5.5 5.5
53.9±0.5 56.6±O.5
~Cp
~H
Appr.lRem.
Ref
6.10 6.35
290 350
heat (1,2) heat (3)
99Tl 99Tl
Remarks: (1) data from fitting the stability curve obtained by urea denaturation from 5 to 40°C, see also Table 1 (2) experimental error 5% for ~H, and 10% f
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