Gulnur Arabaci

The Enzymatic Decolorization of Textile Dyes by the Immobilized Polyphenol Oxidase from Quince Leaves

Water pollution due to release of industrial wastewater has already become a serious problem in almost every industry using dyes to color its products. In this work, polyphenol oxidase enzyme from quince (Cydonia Oblonga) leaves immobilized on calcium alginate beads was used for the successful and effective decolorization of textile industrial effluent. Polyphenol oxidase (PPO) enzyme was extracted from quince (Cydonia Oblonga) leaves and immobilized on calcium alginate beads. The kinetic properties of free and immobilized PPO were determined. Quince leaf PPO enzyme stability was increased after immobilization. The immobilized and free enzymes were employed for the decolorization of textile dyes. The dye solutions were prepared in the concentration of 100 mg/L in distilled water and incubated with free and immobilized quince (Cydonia Oblonga) leaf PPO for one hour. The percent decolorization was calculated by taking untreated dye solution. Immobilized PPO was significantly more effective in decolorizing the dyes as compared to free enzyme. Our results showed that the immobilized quince leaf PPO enzyme could be efficiently used for the removal of synthetic dyes from industrial effluents.

Purification of polyphenol oxidase from borage (Trachystemon orientalis L.) by using three-phase partitioning and investigation of kinetic properties.

In this study a Polyphenol oxidase from borage plant was purified with 3.59-fold enrichment in the specific activity and 68.75% recovery of the total activity by using three-phase partitioning purification technique for the first time. Its molecular weight was found around 80kDa with sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimum pH and temperature values of the enzyme for the used four substrates ranged between the pH 5.0-7.5 and 5-30°C. The kcat/Km values showed that the enzyme has the greatest reactivity toward caffeic acid among the substrates used. Ascorbic acid, l-cysteine and sodium metabisulfite markedly inhibited borage polyphenol oxidase activity.

α- or β-Substituted functional phthalocyanines bearing thiophen-3-ylmethanol substituents: synthesis, characterization, aggregation behavior and antioxidant activity

The tetra α- or β-thiophene substituted metal and metal-free phthalocyanines (Pcs) M[Pc(α-OCH2Thiopen)4] and M[Pc(β-OCH2Thiopen)4] {(α-ThMet-MPc), (β-ThMet-MPc) [ThMet: Thiophene methoxy], M = Zn(II), Co(II) and, 2H} were synthesized from the corresponding 3’-(thiophen-3-ylmethoxy)phthalonitrile or 4’-(thiophen-3-ylmethoxy)phthalonitrile (ThMePN). The structural characterization, spectral, and antioxidant properties of a series of new Pcs were also presented. Both α- and β-substituted Pc complexes increased solubility in polar solvents, such as THF, DMF, and DMSO. FT-IR, 1H-NMR, 13C-NMR, UV–vis, MALDI-TOF/MS spectral, and elemental analysis data were used to characterize the compounds. The aggregation behaviors of 3–8 were also investigated at different concentrations in THF. Antioxidant test methods, α,α-diphenyl-β-picrylhydrazyl radical scavenging activity, metal chelating activity, and reducing power, were used to determine the antioxidant activities. 6 showed very good ferrous ion chelating activity of 81 ± 1%. 6, 5, 4, and 3 showed better reducing power than trolox, ascorbic, acid and butylated hydroxytoluene, commercially used antioxidants. Graphical Abstrcat

Determination of SOD, POD, PPO and CAT Enzyme Activities in Rumex obtusifolius L.

Aims: The purpose of this study was to measure antioxidant enzyme (polyphenol oxidase, peroxidase, catalase and superoxide dismutase) activities of crude extract of Rumex obtusifolius L. in order to gain insight about this plant’s antioxidant potential. Study Design: The study was composed of the collection of plant material, extractions of the antioxidant enzymes, activity measurements of the enzymes and finally evaluation of the experimental results. Place and Duration of Study: Department of Chemistry (biochemistry laboratories), Faculty of Science and Arts of Sakarya University, between June 2015 and July 2015. Methodology: Enzymatic antioxidant activity of this plant was investigated by carrying out catalase, superoxide dismutase, peroxidase and polyphenol oxidase enzyme activity assays. Enzyme activities of the crude extract were measured by using spectrophotometric method. Optimum pH and temperature values of each enzyme were also determined for measurement of enzyme activities in ideal conditions. Results: Finally, our results showed that Rumex obtusifolius L. crude extract had good activity for all the enzymatic procedures tested. The activity levels of enzymatic antioxidants polyphenol oxidase, peroxidase, catalase and superoxide dismutase of the plant were found to be 12.8; 195.2; Original Research Article Alici and Arabaci; ARRB, 11(3): 1-7, 2016; Article no.ARRB.29809 2 38.7; 11.6 EU/mL, respectively. Optimum pH and temperature values of all the enzymes (except PPO: optimum temperature 30°C) tested were also foun d to be 7.0 and 25°C, respectively. Conclusion: Our results demonstrate that this edible plant, Rumex obtusifolius L., might be a potential source of natural antioxidants with good antioxidant enzyme capacity.

Synthesis, characterization, antioxidant and antibacterial properties of non-peripherally and peripherally tetra-substituted phthalocyanines

abstract This study focuses on the synthesis, spectral, antioxidant and antibacterial properties of the metal-free, zinc and cobalt phthalocyanines (3–8) bearing 4-methoxy-phenoxy substituents on the nonperipheral [(1(4), 8(11), 15(18), 22(25)] or peripheral [2(3), 9(10), 16(17), 23(24)] positions. The new synthesized complexes 7 and 8 have been characterized by elemental analysis, FT-IR, MALDI-MS, and UV-vis spectral data. The antioxidant activities of all tested compounds were investigated by applying three different antioxidant methods such as radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl, chelating ability to ferrous ions and reducing power activity methods. In addition, the antibacterial activities of the compounds were screened by disc diffusion method against one gram-negative and four gram-positive bacteria. The tested phthalocyanine compounds showed very good antioxidant activity and promising antibacterial properties.

Partial Purification and Characterization of Polyphenol Oxidase from the Wild Edible Mushroom Lepiota Procera Using Three-Phase Partitioning

Abstract Polyphenol oxidase (PPO) from the wild edible mushroom Lepiota procera is partially purified and biochemically characterized using three-phase partitioning (TPP), which is an easily applied and effective method. This method includes ammonium sulfate saturation at different concentrations, t-butanol addition (1:1; 1:5), and adjustment of pH. Optimum purification parameters with 20% ammonium sulfate saturation and 1:1 t-butanol conditions led to the highest activity at bottom phase with 8.4 fold purification. Sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed the molecular weight of the purified enzyme to be 35 kDa. The partially purified PPO presented a high level of activity with L-DOPA (Michaelis-Menten constant, Km – 0.12 mM), followed by caffeic acid (0.27 mM) and 4-methylcatechol (0.46 mM) and it is classified as a catecholase type of PPO. The enzyme had peak activity at a temperature of 40 °C and a pH value of 7.0. These results demonstrate a new enzyme source and easy purification method, useful for various industrial applications.

A novel serine protease from strawberry (Fragaria ananassa): Purification and biochemical characterization

In this study, a protease enzyme was purified from strawberry by using Sepharose-4B-l-tyrosine-p-amino benzoic acid affinity chromatography. The molecular weight of pure protease was determined 65.8 kDa by SDS-PAGE. The single band observed on the gel showed that the enzyme had a single polypeptide chain and was successfully purified. Purification of the protease by the chromatographic method resulted in a 395.6-fold increase in specific activity (3600 U/mg). Optimum pH and temperature for the enzyme were 6 and 40 °C, respectively. The protease was stable at a wide temperature range of 40 to 70 °C and a pH range of 3.0 to 9.0. Co2+ ions stimulated protease activity very strongly. Cu2+, Hg2+, Cd2+ and Mn2+ ions significantly inhibited protease activity. While 2-propanol completely inhibited the enzyme, the enzyme maintained its activity better in the presence of ethanol and methanol. The strawberry protease showed the highest specificity towards hemoglobin among all the natural substrates tested. The specificity of the enzyme towards synthetic substrates was also investigated and it was concluded that it has broad substrate specificity. The obtained results indicated that this purified protease was highly-likely a serine protease and its activity was significantly affected by the presence of metal ions.

The metal effect on the Polyphenol oxidase enzyme from borage(Trachystemon orientalis) plant

In this study, Polyphenol oxidase was extracted from Borage plant (Trachystemon orientalis) and the crude extract was used for the assays. Its pH and temperature optima for 4-methyl cathecol were 5.0 and 5° C, respectively. Km of this enzyme was 4.55 mM for 4-methyl cathecol. We also found that the enzyme was activated by Fe3+ , Mg 2+ , Zn 2+ , Cu 2+ , Ca 2+ , K + , but inhibited by Hg2+ , Mn 2+ , Ni 2+ , Sn 2+ , Na + . Ba 2+ , Al 3+ and Pb2+ metal ions both activated and inhibited the enzyme at different concentrations.