Purification and characterization of a peroxidase present in xilopodium exsudates of umbu plants (Spondias tuberosa A.)

Abstract

Umbu plants are drought resistant trees which are able to store water and several other substances into its adapted root, named xylopodium. The exsudate from xilopodium is a natural solution rich in salts, sugars and a little concentration of proteins. In this work, we report the purification of a peroxidase (POX) from umbu xilopodium exsudate by direct extraction from polyacrylamide electrophoresis gels. Umbu POX showed optimum activity at pHs around 6.0 to 7.0 and high thermal resistance after incubation at 70°C for 6 min. POX activity present in crude extracts was more heat-resistant than in its purified form. When assayed with metal ions, umbu POX activity was shown to be inhibited by Mn 2+ and stimulated by Ca 2+ and Mg 2+ ; it was also inhibited by sodium azide (concentrations higher then 1 mM) and not inhibited by either EDTA or tropolone. POX Km values for guaiacol and methylcatechol substrates were 6.83 and 22.25, respectively. The enzyme is proposed to be a guaiacol peroxidase and was seen to be located at higher concentrations in the outermost layers of xylopodium tissue, such as the endoderm.

Production and Characterization of Hydrocarbon Degrading Peroxidase from Rhizopus and Saccharomyces Species

“…Also, another study by Bhatti et al (2012) has shown peroxidase from Raphanus sativus to have an optimum activity at pH 4.0. The findings from this study agrees with findings of Pinto et al (2015) who observed a broad range of pH 4.5 up to 7.5 for umbu peroxidase and its activity maintained at 70% levels. The pH curve also showed a bell-like shape distribution suggesting an involvement of two amino acid residues in catalysis as reported by Pinto et al (2015).…”

“…Adefila et al (2012) reported similarly in their work that Ca 2+ and Mn 2+ were potent activators of αamylase. Pinto et al (2015) reported a stimulatory effect of Ca 2+ on peroxidase present in Xilopodium exsudates of umbu plants, with Mg 2+ having similar effect but at a lower concentration than that of Ca 2+ , whereas Mn 2+ displayed inhibitory effect. However, Pb 2+ inhibited the activity of the enzyme.…”

“…However, the Vmax (20 u/ml/min) was greater as compared to that of Kim and Lee with Vmax 0.032 u/ml/min for o-dianisidine and 0.138 u/ml/min for hydrogen peroxide, for peroxidase from Raphanus sativus. Pinto et al (2015) reported that peroxidases oxidize several different substrates in the presence of hydrogen peroxide. Peroxidase showed high affinity and catalytic efficiency towards the Odianisidine substrate.…”

“…Hamid et al (2016) reported in his review, that peroxidase are involved in the manufacturing of many aromatic complexes, elimination of phenolics complexes from waste water and peroxides from foods, beverage and industrial wastes. However, its isolated form, peroxidases are among the most useful enzymes in biotechnology, since several industrial processes can be performed by this kind of enzyme, such as soil detoxification and bioremediation of waste waters contaminated with phenols, cresols and chlorinated phenols (Pinto et al, 2015).…”

Etude comparative des peroxydases de dix (10) plantes supérieures couramment rencontrées au Burkina Faso

“…Ainsi des activités inferieures ont été reportées chez d'autres plantes à savoir, le blé (Triticum aestivum ssp vulgare) dont l'activité est de 0,02 U/mg (Altin et al, 2017), le palmier (Phoenix dactylifera L.) dont l'activité spécifique est de 53,3 U/mg (Al-Senaidy et Ismael, 2011). Cependant, des activités supérieures ont été rapportées chez d'autres plantes à savoir radis (Raphanus sativus) dont l'activité spécifique est de 226 U/mg (Diao et al, 2018), Metroxylon sagu et Spondias tuberosa dont les activités spécifiques sont supérieures à 800 U/mg (Onsa et al, 2004 ;Pinto et al, 2015). L'activité spécifique des peroxydases de Daucus carota est de 109,8 U/mg.…”