Kinetic characterisation and thermal inactivation study of red alga (Mastocarpus stellatus) peroxidase
Autor/es
Núñez Delicado, Estrella; Fortea Gorbe, María Isabel; López Miranda, Santiago; Serrano Martínez, Ana Agustina; Hernández Sánchez, Pilar; [et al.]Fecha
2011Disciplina/s
Ciencias de la AlimentaciónMateria/s
PeroxidaseAscorbic acid
Metabisulphite L-Cysteine
Kinetic parameters
Thermal inactivation SDS
Mastocarpus stellatus
Seaweed foods
Resumen
Peroxidase (POD) was extracted from red alga (Mastocarpus stellatus) using Triton X-114 and characterised
by UV-spectrophotometry. Optimum activity using 2,2´ -azinobis(3-ethylbenzothiazolinesulphonic
acid) (ABTS) as the H-donor was obtained at pH 5.0. In the presence of the anionic detergent, sodium
dodecyl sulphate (SDS), however, POD was inactivated at all the pH values studied and totally inactivated
at 1 mM SDS. When the enzyme was kinetically characterised, the KM and Vm values for ABTS were found
to be 13 mM and 40 lM/min, respectively. In addition, when the H2O2 concentration was increased, at a
fixed concentration of ABTS, the activity was inhibited at the highest H2O2 concentrations. In a study of
the effect of several reducing agents, L-cysteine was found to be the most active. A thermal inactivation
study showed a first-order inactivation kinetic, and the Arrhenius plot yielded a straight line with a slope
equivalent to an activation energy of 121.6 kJ/mol. Signifi...