Kinetic characterisation and thermal inactivation study of red alga (Mastocarpus stellatus) peroxidase

• Published in: Food chemistry Vol. 127; no. 3; pp. 1091 - 1096
• Main Authors: Fortea, M.I., López-Miranda, S., Serrano-Martínez, A., Hernández-Sánchez, P., Zafrilla, M.P., Martínez-Cachá, A., Núñez-Delicado, E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2011; Elsevier
• Subjects: Ascorbic acid; Biological and medical sciences; Food industries; Fundamental and applied biological sciences. Psychology; Kinetic parameters; l-Cysteine; Mastocarpus stellatus; Metabisulphite; Peroxidase; SDS; Seaweed foods; Thermal inactivation; l-Cysteine; SDS; Ascorbic acid; Kinetic parameters; Thermal inactivation; Metabisulphite; Peroxidase; Mastocarpus stellatus; Seaweed foods; Cysteine; Enzyme; Algae; Vitamin; Inactivation; Red; Peroxidases; Aminoacid; L-Cysteine; Oxidoreductases; Kinetics; Kinetic parameter; Food
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2011.01.105

► Detailed kinetic study of Mastocarpus stellatus seaweed POD isolated using TX-114. ► M. stellatus POD was inactivated by the anionic detergent SDS. ► POD inactivated by reducing agents as l-cysteine, ascorbic acid and metabisulphite. ► A very thermolabile POD compared with other extracted from plant source. 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.