Ageing
Henry J. Woodford in Essential Geriatrics, 2022
Cellular damage can be caused by internal and external factors. External factors include solar radiation and damage secondary to smoking. Internal factors include the formation of harmful molecules during oxidative respiration. Free radicals contain an unpaired electron in their outer shell (also termed ‘reactive oxygen species'), which makes them likely to interact with other molecules and cause harm. They are typically formed during the mitochondrial electron transport process. One example is superoxide (O2-), which can be converted to hydrogen peroxide (H2O2) by superoxide dismutase. Hydrogen peroxide is metabolised by the enzyme catalase. This may lead to the production of hydroxyl radicals that may also cause intracellular damage but can be neutralised by the naturally occurring compound glutathione.
Biochemical Methods of Studying Hepatotoxicity
Robert G. Meeks, Steadman D. Harrison, Richard J. Bull in Hepatotoxicology, 2020
This is also known as hydrogen peroxide, hydrogen peroxide oxidoreductase, and EC 1.11.1.6. Catalase acts on hydrogen peroxides, generated either via metabolism of endogenous substances or via metabolism of exogenous compounds. Since it removes reactive hydrogen peroxide from the cell, it is important in detoxification mechanism. Several methods have been employed for measuring catalase activity. However, most of them have some drawbacks in the accuracy of measuring the catalysis of hydrogen peroxide. The major factor in variability is the rapidity of its action on H2O2. The method described here is a simple spectrophotometric method and yet is fairly sensitive and specific (Beers and Sizer, 1952) and directly measures the decrease in H2O2. Using digital spectrophotometer with built in kinetic programs and temperature control system, it is possible to accurately measure the catalysis of H2O2 by catalase.
Alcohol
S.J. Mulé, Henry Brill in Chemical and Biological Aspects of Drug Dependence, 2019
Catalase is an ubiquitous enzyme, found in most animal tissues including the liver. In vitro, it can catalyze the peroxidative conversion of alcohols to the corresponding aldehydes.51 Its role in vivo is still the subject of debate. It participates in the oxidation of methanol, at least in the rat, whereas in the monkey, alcohol dehydrogenase may play a greater role in that respect.52 Which enzyme is involved in methanol oxidation in man has not been elucidated. Similarly, it is not known to what extent catalase participates in the in vivo oxidation of ethanol. Catalase was thought to have no role in ethanol metabolism in vivo,53 an opinion supported by the observation that amino-thiazole, a catalase inhibitor in vivo, does not affect rates of ethanol metabolism.54
Specific and combined effects of dietary ethanol and arginine on Drosophila melanogaster
Published in Drug and Chemical Toxicology, 2023
Maria M. Bayliak, Oleh I. Demianchuk, Dmytro V. Gospodaryov, Vitalii A. Balatskyi, Volodymyr I. Lushchak
The transcriptional and posttranslational regulation of such antioxidant and related enzymes as catalase, G6PDH, and GST is relatively poorly investigated in D. melanogaster. It is known that transcriptional regulator DREF (DNA replication related element binding factor) up-regulates catalase expression (Park et al. 2004). At the same time, DREF is regulated by mTOR (Texada et al. 2020). However, this route of regulation would explain an increase in catalase activity rather than the decrease as we observe in our case (Figure 5). On the other hand, catalase is a heme-containing enzyme. Nitric oxide produced from arginine by nitric oxide synthase was shown to inhibit heme-containing proteins such as catalase (Purwar et al. 2011). The other two enzymes, G6PDH and GST can be regulated transcriptionally by different factors, in particular, Nrf2 (CncC in Drosophila) (Gospodaryov et al. 2020).
Justicia carnea extracts ameliorated hepatocellular damage in streptozotocin-induced type 1 diabetic male rats via decrease in oxidative stress, inflammation and increasing other risk markers
Published in Biomarkers, 2023
John Adeolu Falode, Oluwaseun Igbekele Ajayi, Tolulope Victoria Isinkaye, Akinwunmi Oluwaseun Adeoye, Basiru Olaitan Ajiboye, Bartholomew I. C. Brai
A decrease in the defensive systems of enzymatic and non-enzymatic antioxidants is shown by the rise in MDA, which promotes lipid peroxidation (Saddala et al.2013). The antioxidant enzyme known as SOD is responsible for catalysing the conversion of superanion into hydrogen peroxide and molecular oxygen (Wang et al.2012). SOD has vital protective functions against cellular and histological harm caused by ROS. It speeds up the process of converting superoxide radicals into hydrogen peroxide, which can then be transformed into oxygen and water in the presence of other enzymes (Buldak et al.2014). An antioxidant enzyme called catalase (CAT) is almost universally found in all living things. It is crucial in the fight against conditions like diabetes and cardiovascular illnesses that are brought on by oxidative. When compared to the diabetic control (STZ-induced) group, we saw that the administration of J. carnea to diabetic rats significantly (p < 0.05) decreased the MDA, SOD, CAT and GST levels in the liver of the extract-treated groups (JCCD, JBPD and JFPD), while significantly (p < 0.05) increased the GSH levels. These findings are in line with a prior study (Ani et al.2020) that revealed the antioxidant properties of J. carnea. Similarly, metformin’s ability to protect against oxidative stress has been well-established (Nesti and Natali 2017; Loi et al.2019; Abdulkarim et al.2021).
Chronic oral exposure of aluminum chloride in rat modulates molecular and functional neurotoxic markers relevant to Alzheimer’s disease
Published in Toxicology Mechanisms and Methods, 2022
Mangaldeep Dey, Rakesh Kumar Singh
Existing literature indicates that oxidative stress and nitrosative stress is a major causative factors in aluminum-induced neurotoxicity. The two main consequences of oxidative stress are increased pro-oxidant and decreased antioxidants levels. We investigated the levels of three antioxidant markers in the brain including GSH, SOD and catalase (Figure 3(A–C)). There was a significant difference in brain GSH level was observed in this study. Exposures of aluminum, for 24 weeks resulted in a significant depletion in GSH level as compared to the control group. SOD is one of the important enzymes in maintaining the intrinsic antioxidant defense system. Chronic exposure to aluminum chloride marginally decreased the SOD level; however, it was not found to be significant. Catalase is one of the most crucial antioxidant enzymes which mitigates oxidative stress by destroying the cellular hydrogen peroxide to water. Chronic exposure to aluminum significantly decreased the catalase level in the brain compared to control rats.