Bioenergetics
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan in Strength and Conditioning in Sports, 2023
The phosphagen system attains increased activation at the initiation of all exercise regardless of intensity but is primarily engaged in providing energy for short-term high-intensity activities such as weight-training exercise and sprinting. (14, 35, 50). The phosphagen system involves ATP and creatine phosphate (PCr), and three enzymes: myosin ATPase, creatine kinase (CK) and myokinase. Energy is supplied for muscle contraction by the hydrolysis of ATP, catalyzed by myosin ATPase, producing ADP and inorganic phosphate (Pi). During high-intensity work, CK catalyzes the reaction in which PCr donates its phosphate group to ADP, re-forming ATP and producing creatine (Cr). These reactions provide energy rapidly and at a high rate:
Exercise Redox Signalling
James N. Cobley, Gareth W. Davison in Oxidative Eustress in Exercise Physiology, 2022
In the onset of muscle contraction, a high demand for ATP drives the cellular metabolism to provide energy for ATPases, calcium handling events, and promotion of the crossbridge interaction between actin and myosin filaments. Within milliseconds, ATP demand rapidly induces an orchestrated metabolic flow to match the demand for ATP. Initially, mitochondria were believed to be the main source of ROS following exercise based on an obvious correlation between increased oxygen consumption and increased ATP production. It has been shown that at least 11 mitochondrial sites can generate ROS in mammals that depends on the bioenergetic state (Wong et al., 2017). Remarkably, during exercise mitochondria operate in state 3 (also known as the maximal ADP stimulated respiration) and thereby reduce ROS generation, contrary to what is observed in the basal conditions, where mitochondria operate in respiration state 4 (Goncalves et al., 2015). Elegantly, when mitochondria are exposed to a condition that mimics exercise, H2O2 is considerably reduced (Goncalves et al., 2015; Jackson et al., 2016) and also confirmed using an in vivo mice model of exercise (Henríquez-Olguin et al., 2019).
Maturation of Brain ATP Metabolism
Richard A. Jonas, Jane W. Newburger, Joseph J. Volpe, John W. Kirklin in Brain Injury and Pediatric Cardiac Surgery, 2019
The development of cerebral ATPases in rat brain has been studied less than the ATP synthetic pathways. In the adult rabbit hippocampus, there are regional differences in the activity of Na,K-ATPase, the predominant ATPase of brain.62 Within each region, there is a maturational increase in activity between days 8 and 15. The Na,K-ATPases from rabbit cerebral cortical neurons, glial-enriched fraction, and synaptosome-enriched fraction show the same kinetic properties, suggesting that the same enzyme is present in these sites.63 However, a recent developmental study demonstrates three Na,K-ATPase isoenzymes which are present throughout the brain in different relative concentrations.64 Only one of these isoenzymes increases during the first month of life in the rat brain. Neurons contain all three isoenzymes while glia contain only two, but both cell groups contain the isoenzyme that increases with postnatal brain metabolic maturation.65 The subcellular localizations and physiological functions of these ATPases are unknown.
Kolaviron modulates dysregulated metabolism in oxidative pancreatic injury and inhibits intestinal glucose absorption with concomitant stimulation of muscle glucose uptake
Published in Archives of Physiology and Biochemistry, 2023
Veronica F. Salau, Ochuko L. Erukainure, Neil A. Koorbanally, Md. Shahidul Islam
Purinergic enzymes catalyse the production of adenosines which are involved in the attenuation of inflammation and tissue injury (Ademiluyi et al.2016). ATPase is a purinergic enzyme that catalyses the phospho-hydrolysis of adenosine triphosphate (ATP) to ADP. Ca2+ -Mg2+ -ATPase has been implicated in intracellular calcium homeostasis, as it regulates the inflow of Ca2+ through the cell membrane into the cell. High calcium overload has been implicated in production of pro-inflammatory mediators which is strongly linked to a decrease in the activity of Ca2+ -Mg2+ -ATPase (Qiu et al.2004). Increased production of free radicals during pancreatic injury leads to a redistribution of membrane phospholipids and thus, a contributory factor to the inhibition of ATPase activity (Bruce and Elliott 2007, Mukherjee et al.2008). In the present study, the decreased ATPase activity in the untreated pancreatic tissue (Figure 8(B)) which corroborates induction of oxidative stress (Figure 6) may insinuate Ca2+ overload and inflammation. Treatment with kolaviron increased the activity of ATPase which may indicate an anti-inflammatory role of kolaviron as supported by the decreased NO levels in treated tissues (Figure 7) and suppression of oxidative stress (Figure 6).
3,4-Dihydroxybenzaldehyde attenuates pentachlorophenol-induced cytotoxicity, DNA damage and collapse of mitochondrial membrane potential in isolated human blood cells
Published in Drug and Chemical Toxicology, 2022
Nikhil Maheshwari, Riaz Mahmood
The protective effect of DHB on PCP-induced damage to membrane-bound enzymes like ATPases and AChE was evaluated next. ATPases maintain nutrient and substrate transport, cell adhesion and ionic homeostasis. RBC Na+,K+-ATPase is essentially required in the regulation of intra-extracellular cation homeostasis. PCP and several other chlorophenols uncouple oxidative phosphorylation and also inhibit ATPase and several other enzymes (Jorens and Schepens 1993). PCP treatment reduced total and Na+,K+-ATPase activities to 62% and 44% of control cells. Alteration in transport enzyme activities is thought to be linked to several complications of diabetes mellitus. Lowered ATPase activity also alters the surface area to volume ratio, membrane fluidity and cytoplasmic rheology which leads to RBC deformability (Radosinska and Vrbjar 2016). In presence of DHB, both enzyme activities were significantly restored.
Evaluation of the acute toxic effect of azoxystrobin on non-target crayfish (Astacus leptodactylus Eschscholtz, 1823) by using oxidative stress enzymes, ATPases and cholinesterase as biomarkers
Published in Drug and Chemical Toxicology, 2021
Aysel Alkan Uçkun, Özden Barım Öz
Pesticides can induce oxidative stress by increasing the production of free radicals, changing in antioxidant enzyme activities and lipid peroxidation (Abdollahi et al. 2004). In this study, to determine the effect of azoxystrobin on oxidative stress, GSH and MDA levels were measured together with SOD, GPx, GST, GR enzyme activities. Most pesticides create toxicity by inhibiting the acetylcholinesterase enzyme, which disrupts acetylcholine, an important neurotransmitter in the central nervous system of organisms (Jones 2005). To determine the neurodegenerative effect of azoxystrobin in crayfish, AChE was preferred as one of the most commonly used markers in toxicity studies. ATPases are enzymes that have important functions, such as maintaining ion balance, regulating electrochemical gradient and cell volume in aquatic organisms (Loro et al. 2014). Increasing or decreasing in the activity of ATPases is considered a vital index as a potential indicator of levels of environmental pollutants and toxic stress (Thaker et al. 1996). Therefore, in this study, the activities of ATPases (Na+/K+ -ATPase, Mg2+ -ATPase, Ca2+ -ATPase and Total ATPase) were also measured in the evaluation of the acute toxicity of azoxystrobin.
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