title: Kinetic characterisation and thermal inactivation study of red alga (Mastocarpus stellatus) peroxidase.
abstract: 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 1mM SDS. When the enzyme was kinetically characterised, the KM and Vm values for ABTS were found to be 13mM and 40μM/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 121.6kJ/mol. Significant inactivation occurred at temperatures of>35°C, with>90% of the relative activity being lost after only 5min of incubation at 48.4°C.
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain.
authors.forename: M I
authors.initials: MI
authors.lastname: Fortea
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain.
authors.forename: S
authors.initials: S
authors.lastname: López-Miranda
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Serrano-Martínez
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Hernández-Sánchez
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain.
authors.forename: M P
authors.initials: MP
authors.lastname: Zafrilla
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Martínez-Cachá
authors.affiliation: Dpto. de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Avenida de los Jerónimos s/n, 30107 Guadalupe, Murcia, Spain. Electronic address: enunez@pdi.ucam.edu.
authors.forename: E
authors.initials: E
authors.lastname: Núñez-Delicado
keywords: Ascorbic acid; Kinetic parameters; Mastocarpus stellatus; Metabisulphite; Peroxidase; SDS; Seaweed foods; Thermal inactivation; l-Cysteine