Sürdürülebilir Kalkınma Amaçları
Yazarlar
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ1Purification of catalase enzyme from Thymus nummularius and examination of the effects of varying glucose concentrations on catalase activity
Toprak, Esma; Güleşci, Nuri
Catalase (EC 1.11.1.6), an antioxidant enzyme, breaks down reactive oxygen species, hydrogen peroxide (H2O2), into water and oxygen. In this study, the partial purification of catalase was obtained from Thymus nummularius M. Bieb. through ammonium sulfate (NH4)2SO4 precipitation, dialysis, and desalting/buffer exchange by using a PD-10 Sephadex G-25 M column. The isolated enzyme had a specific activity of 1294.45 U/mg protein and a purification fold of 7.80. The SDS-PAGE analysis indicated a molecular weight ranging between 37 and 50 kDa. The optimal pH and temperature for catalase activity were determined to be pH 8.0 and 25 °C, respectively. The kinetic parameters, maximum velocity (Vmax) 277.78 U/mL and Michaelis constant (KM) 34.17 mM were estimated from Lineweaver-Burk plots. Furthermore, catalase activity was evaluated at glucose concentrations ranging between 25 and 500 ppm. Enzyme activity increased at 25–100 ppm, significantly decreased at 250 ppm, and then increased again at 500 ppm. These results suggest that glucose may modulate catalase activity in a concentration-dependent manner. Even though the exact regulatory mechanism remains unclear, this effect could have potential implications for glucose-sensitive metabolic systems.
- MakaleYalnız künye2021Scopus SJRQ2N epeta meyeri essential oil ameliorates fungal infection and the antioxidant response in grapevines (Vitis vinifera) infections by gray mold (Botrytis cinerea)
Karakuş, Sinem; Atici, Ökkeş; Köse, Cafer; Aydin, İhsan
The essential oil (EO) obtained from Nepeta meyeri Benth. used to struggle allelopathically with gray mold (Botrytis cinerea Pers.), which causes significant damage to vineyards (Vitis vinifera L. cv. Karaerik). The EO from N. meyeri was determined to contain 4aα, 7α, 7aα-nepetalactone (71.68%) at the highest rate when analyzed with GC/MS. Then, the doses (0.6, 0.8, and 1.0 µL/leaf) of 1 ppm EO solution were applied to the leaves together with the fungus inoculation (EO + F), as well as 1 day (EO + F1D) and 2 days (EO + F2D) before inoculation. The fungus application alone was evaluated as a control. Seven days after the inoculations, fungus development, lipid peroxidation level (as malondialdehyde), the contents of reactive oxygen species (ROS), photosynthetic pigments and soluble proteins, and the activities of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, and glutathione reductase) were determined in the leaves. Findings revealed that EO + F1D among the applications and 1.0 µL/leaf among the EO doses significantly prevented fungus development on the leaf, compared to the control. Moreover, the same applications decreased ROS levels, such as H2O2 and O2·− and lipid peroxidation, while they increased antioxidant enzyme activities, as well as chlorophyll and soluble protein contents. Therefore, it can be suggested that the EO from N. meyeri has a potentially powerful usage as biofungicide in the allelopathic struggle against the infection of B. cinerea in vineyards.
AtıfScopus5WoS4OpenAlex6İncele