Catalase from the thermophilic fungus Mycothermus thermophilus is a bifunctional enzyme with a secondary phenol oxidase activity (CATPO). MtCATPO catalyses the oxidation of catechol, chlorogenic acid, caffeic acid and (+)-catechin to yield mainly dimers, and higher molecular weight oligomers and polymers. The role of this phenol oxidase activity is not known. Here, the antioxidant capacities (AC) of the phenolic substrates in the absence and presence of MtCATPO were compared. The oxidized products displayed enhanced AC reaching a maximum of 2.4-fold with catechol. Other phenol oxidases (laccase and tyrosinase) did not yield AC enhancement to the same extent. MtCATPO-treatment increased AC of green and black tea infusions, as well as water extracts of samples collected from a black tea production line up to 28%. The bifunctional MtCATPO appears to be an important antioxidant enzyme with a wide range of potential applications in the food, neutraceuticals and pharmaceuticals industry.

South East Anatolia Region has a large genetic plant diversity due to its physical and different climatic charesteristics. These plants are potential sources of antioxidants that prevent oxidative stress caused by oxygen and photons. In recent years, it has become important to study the antioxidant capacity of many molecules found naturally in foods and biological systems. The reason for this is that it is believed that when the consumption of food rich in antioxidants is increased, the risk of developing different degenerative diseases will be reduced. In this study, it was aimed to measure the antoxidant capacity of Quercus infectoria, G.olivier gal seeds grown in Southeastern Anatolia. Q. infectoria gal seeds from Sanlıurfa province were used in our study. Q. infectoria gal seeds were extracted with water, ethanol and methanol and then antioxidant enzyme activities (catalase and superoxide dismutase) and malondialdehyde levels, which are indicators of oxidative stress were determined by spectrophotometric methods. It was found that the antioxidant capacity (catalase and superoxide dismutase activities) of extracts obtained from ethanol and methanol were higher and their malondialdehyde levels were statistically lower than those obtained from water. However, it was determined that there was no statistically significant difference between the antioxidant capacity and malondialdehyde levels of the extracts obtained from methanol compared to the extracts obtained from ethanol. It has been concluded that Q. infectoria gal seed has a effective antioxidant effect. In addition, it was observed that extracts obtained from ethanol and methanol have higher antioxidant capacity than extracts obtained from water.

Analysing the factors driving the population size and activities of soil microorganisms is important for understanding the soil ecosystem’s structure and functioning. For this purpose, the soil enzymes are used as an indicator of soil microbial activity and soil fertility. Although there are many studies on the distribution and activities of various soil enzymes in soils under monoculture or crop alternation conditions, there are only few studies examining the ecological relationship in natural ecosystems, especially by using enzymes. In this study, it was aimed to determine the effect of different land uses on the catalase enzyme activity in soil. For this purpose, the catalase enzyme activities in soil samples taken from 0-5cm and 5-10cm depths in agricultural, forest, and pasture lands in north and south exposures were determined and the effects of different land use, exposure, and soil depth conditions on the enzyme activities were investigated. At the end of the study, it was determined that the catalase enzyme activity significantly differed by the land use and the highest level of catalase enzyme activity in both south and north exposures and at both depth levels was found in forest soils, whereas the lowest level of activity was found in agricultural lands in north exposure and pasture soils in south exposure.