A novel peroxidase from runner bean (Phaseolus coccineus L.): Enhanced affinity purification, characterization, and dye decolorization activity

Simple two-step purification and characterisation of peroxidase from Citrullus colocynthis

Peroxidase is a biotechnologically important enzyme. The purification of peroxidase from the root of Citrullus colocynthis was carried out in a simple two-step process with maximum purity level. The sample was extracted in a high salt buffer, and the enzyme was partially purified with a Q-Sepharose anion exchange column. Final purification was carried out with HighLoad 16/600 Superdex G-75 column. The purified protein was analysed with SDS gel electrophoresis, which suggested a single band of approximately 35 kDa. Further, the enzyme was identified with the help of Mass spectrometric analysis using an ESI-QTOF Mass spectrometer. The study will be helpful for the isolation and its commercial uses in biotechnology.

Synthesis and Characterization of Cross-Linked Aggregates of Peroxidase from Megathyrsus maximus (Guinea Grass) and Their Application for Indigo Carmine Decolorization

We present the synthesis of a cross-linking enzyme aggregate (CLEAS) of a peroxidase from Megathyrsus maximus (Guinea Grass) (GGP). The biocatalyst was produced using 50%v/v ethanol and 0.88%w/v glutaraldehyde for 1 h under stirring. The immobilization yield was 93.74% and the specific activity was 36.75 U mg-1. The biocatalyst surpassed by 61% the free enzyme activity at the optimal pH value (pH 6 for both preparations), becoming this increase in activity almost 10-fold at pH 9. GGP-CLEAS exhibited a higher thermal stability (2-4 folds) and was more stable towards hydrogen peroxide than the free enzyme (2-3 folds). GGP-CLEAS removes over 80% of 0.05 mM indigo carmine at pH 5, in the presence of 0.55 mM H2O2 after 60 min of reaction, a much higher value than when using the free enzyme. The operational stability showed a decrease of enzyme activity (over 60% in 4 cycles), very likely related to suicide inhibition.

Development of a new affinity chromatography method for purification of horseradish peroxidase enzyme

In this study, benzohydroxamic acid molecules were synthesized from methyl 4-amino-2-methoxy, methyl 4-amino-3-nitro, methyl 4-amino-3-methyl, and methyl 4-amino-3-chloro benzoate molecules, and the horseradish peroxidase (HRP) enzyme was purified in one step using the affinity chromatography technique for the first time. The IC50 and Ki values for the 4-amino 3-methyl benzohydroxamic acid molecule were 0.136 and 0.132 ± 0.054 μM, respectively, while the IC50 and Ki values for the 4-amino-3-nitro benzohydroxamic acid molecule were 56.00 and 51.90 ± 9.90 μM, respectively. It was found that the IC50 and Ki values for the 4-amino-3-chloro benzohydroxamic acid molecule were 218.33 and 175.67 ± 43.78 μM, respectively, whereas the IC50 and Ki values for the 4-amino-2-methoxy benzohydroxamic acid molecule were 306.00 and 218.00 ± 68.80 μM, respectively. The HRP enzyme was synthesized from 4-amino-2-methoxy hydroxamic acid column with a 35.97% yield 601.13 times, 4-amino-3-nitro hydroxamic acid column, with a 14.00% yield 404.11 times, 4-amino-3-methyl hydroxamic acid column with an 8.70% yield 394.88 times, and 4-amino-3-chloro hydroxamic acid column with a 4.48% yield 284.85 times. Thus, the HRP enzyme was purified in a single step with hydroxamic acids, and its molecular weight was found to be 44 kDa. The optimum pH was 8.0, the optimum temperature was 15°C, and the optimum ionic strength was 0.4 M for the purified HRP enzyme.

Enzymatic degradation of azo dyes methylene blue and congo red with peroxidase purified from cauliflower using affinity chromatography technique: Kinetic study, optimization and metal binding activity

The effective results of the enzymatic decolorization of industrial azo dyes found in wastewater, which cause serious health and environmental problems, with peroxidases have recently increased the interest in these enzyme sources. Redox-mediated decolorization of Methylene Blue and Congo Red azo dyes with cauliflower (Brassica oleracea var.botrytis L.) peroxidase (CPOD) purified in one step using 4-amino 3-bromo 2-methyl benzohydrazide molecule was investigated for the first time. The inhibition effect of this molecule, which is used as a ligand in affinity chromatography, on the CPOD enzyme was investigated. The K_i and IC₅₀ values for this enzyme were calculated as 0.113 ± 0.012 mM and 0.196 ± 0.011 mM, respectively. With the affinity gel obtained by binding to the Sepharose-4B-l-tyrosine matrix of this molecule, which shows a reversible inhibition effect, the purification values of CPOD enzyme were determined as 562-fold with a specific activity of 50,250 U mg^-1. The purity of the enzyme was checked by the SDS-PAGE technique and its molecular weight was determined. A single band at 44 kDa was observed for the CPOD enzyme. In dye decolorization studies, the effects of dye, enzyme, and hydrogen peroxide concentrations as well as time, pH, and temperature were investigated. The profiles of the optimum conditions for both dyes were similar, and the percentages of decolorization of Methylene Blue and Congo Red under these conditions were 89% and 83%, respectively, at the end of the 40 min reaction time. Again, when examining the effect of metal ions on enzyme activity, it was found that there was no significant negative change in CPOD.

Using of group-based selected flavonoids as alternative inhibitors for potato polyphenol oxidase

One of the main problems encountered after fresh-cutting of foods is enzymatic browning causing changes in the texture, taste, and color. The variety of physical and chemical-based antibrowning methods was applied to extend the shelf life of these products. Accordingly, methods using natural compounds are of great importance for health. In this study, it was aimed to prevent enzymatic browning in potato (Solanum tuberosum L. cv. Marfona) by limiting the polyphenol oxidase (PPO) activity with selected flavonoids. First of all, we purified the potato PPO (pPPO) by single-step affinity chromatography. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and native PAGE were applied on pPPO. Then, the inhibition effects of 7-hydroxyflavone, 7-hydroxy-4'-nitroisoflavone, myricetin, luteolin, 7-methoxyflavone, 6-fluoroflavone, diosmetin, rutin, and diosmin on purified PPO enzyme were investigated. Kinetic assays indicated that myricetin was a remarkable inhibitor with the K_i value of 5 µM on pPPO. PRACTICAL APPLICATIONS: Potatoes are one of the important diet in many countries. In the processing of potatoes, enzymatic oxidation catalyzed by polyphenol oxidases (PPOs) is lead to losing its taste, flavor, and color. In this current paper, group-based selected flavonoids were proposed as alternative inhibitors of potato PPO enzyme. These flavonoids allowing to limit the PPO activity are commercially available, and they can be potential candidates to be used as antibrowning agents during potato processing.