Thermal stability of peroxidase from Chamaerops excelsa palm tree at pH 3.
The structural stability of a peroxidase, a dimeric protein from palm tree Chamaerops excelsa leaves (CEP), has been characterized by high-sensitivity differential scanning calorimetry, circular dichroism and steady-state tryptophan fluorescence at pH 3. The thermally induced denaturation of CEP at this pH value is irreversible and strongly dependent upon the scan rate, suggesting that this process is under kinetic control. Moreover, thermally induced transitions at this pH value are dependent on the protein concentration, leading to the conclusion that in solution CEP behaves as dimer, which undergoes thermal denaturation coupled with dissociation. Analysis of the kinetic parameters of CEP denaturation at pH 3 was accomplished on the basis of the simple kinetic scheme N-->kD, where k is a first-order kinetic constant that changes with temperature, as given by the Arrhenius equation; N is the native state, and D is the denatured state, and thermodynamic information was obtained by extrapolation of the kinetic transition parameters to an infinite heating rate.
Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain.
Laura S
LS
Zamorano
Susana Barrera
SB
Vilarmau
Juan B
JB
Arellano
Galina G
GG
Zhadan
Nazaret Hidalgo
NH
Cuadrado
Sergey A
SA
Bursakov
Manuel G
MG
Roig
Valery L
VL
Shnyrov
D028023:Arecaceae / Q000201:enzymology*; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D004795:Enzyme Stability; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D009195:Peroxidase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
D009195:Peroxidase