Partial Purification and Thermal Characterization of Peroxidase from Okra (Hibiscus esculentum)

Abstract

Thermal characteristics and substrate specificity of peroxidase (POX) from okra were determined. Crude POX was separated into eight fractions (P1-P8) by DEAE-cellulose chromatography. Heat inactivation of POX was biphasic and fitted to a first-order kinetic model. Inactivation rates of crude POX and eight POX fractions at 70°C varied between (63.499 and 123.809) × 10 -2 min -1 for the heat-labile fractions and (11.255 and 31.441) × 10 -2 min -1 for the heat-stable fractions. Activation energies for the inactivation of crude extract were 37.0 kcal mol -1 with a z-value of 13.8°Cfor the heat-labile fraction and 37.8 kcal mol -1 with a z-value of 13.5°C for the heat-stable fraction. Optimum temperatures were between 30 and 35°C for the crude extract, 60°C for P1-P5 fractions, and more than 65°C for P6-P8 fractions. Among substrates, guaiacol was oxidized primarily by P1-P6 fractions; whereas, pyrogallol and catechin were preferred by P7 and P8, respectively.

Catalytic and kinetic properties of purified Eichhornia crassipes leaf peroxidase

“…Purified peroxidases have been obtained from diverse plant sources (Deepa, Arumughan 2002), such as spring cabbage, soy bean and rice leaves (Ito et al 1991), tea (Kvaratskhelia et al 1997), okra (Yemenicioglu et al 1998), Ipomoea palmetto (Srinivas et al 1999) and Copaifera longsdorffi (Maciel et al 2007). However, less attention has been directed toward sources that are naturally widely available and regarded as unwanted in the environment.…”

Analysis of Thermal Inactivation Kinetics of Membrane-Bound Polyphenol Oxidases and Peroxidases From Metroxylon Sagu

“…Results showed that mPOD‐I had undergone thermal inactivation at 70C with an inactivation rate constant ( k ) of 72.9 × 10 −3 /min compared with that of mPOD‐II with k value at 97.9 × 10 −3 /min. Isoenzymes with different thermal inactivation rate constant were also reported for okra mPOD isoenzymes, where at 70C, the heat labile isoenzyme showed k value at 63.5 × 10 −3 /min and the heat‐stable isoenzyme with k value of 11.26 × 10 −3 /min (Yemenicioglu et al . 1998a).…”

“…Adams (1991) added that this complex could be a carbohydrate, which is known to form a complex with POD molecules. However, Yemenicioglu et al . (1998) reported an exceptionally higher stability for the purified pinto beans mPODs with an inactivation rate ( k ) value at 70C of 24.0 × 10 −3 /min and 32.8 × 10 −3 /min, respectively, for the thermal stable fraction 1 and fraction 2.…”

“…These E a values are higher than that reported for other heat‐stable mPODs such as pinto beans (37.0 kcal/mol; Yemenicioglu et al . 1998b), okra isoperoxidases (37.8 and 37.0 kcal/mol; Yemenicioglu et al . 1998a), Brussels sprouts (35.5 kcal/mol; Regalado et al .…”

Partial Purification of Peroxidase From Iraqi Radish Roots.

“…Peroxidase (POD) an oxidoreductase is a heme protein, catalyses the oxidation of a wide variety of organic and inorganic substrates using hydrogen peroxide as the electron acceptor (1). Peroxidases are widely distributed in living organisms including microorganisms, plants and animals (2).…”