scholarly journals Murburn precepts for redox dynamics in glycolysis, Cori cycle and Warburg effect: Is lactate dehydrogenase a murzyme?

2021 ◽  
Author(s):  
Kelath Murali Manoj ◽  
Vijay Nirusimhan ◽  
Abhinav Parashar ◽  
Jesu Castin E ◽  
Daniel Andrew Gideon
Keyword(s):  
Lactate Dehydrogenase ◽  
Warburg Effect ◽  
Active Sites ◽  
Oxygen Species ◽  
Forward Reaction ◽  
Cori Cycle ◽  
Keto Acids ◽  
Variant Structure ◽  
Redox Conversion ◽  
Redox Dynamics

Physiological redox conversion of alpha-hydroxy/keto acids is believed to be reversibly carried out by (de)hydrogenases, employing nicotinamide cofactors. With lactate dehydrogenase (LDH) as example, we point out that while the utilization of NADH for the reduction of pyruvate to lactate (the post-glycolytic reaction) can be mediated via the classical Michaelis-Menten mechanism, the oxidation of lactate to pyruvate (with or without the uphill reduction of NADH) necessitates alternative physiological approaches. This reaction could be more efficiently coupled/catalyzed with/by murzyme activities, which employ diffusible reactive (oxygen) species (DRS/DROS/ROS). Such a scheme would enable the cellular system to tide over the unfavorable energy barriers of the forward reaction (~450 kJ/mol; earlier considered to be ~25 kJ/mole!), and give kinetically viable conversions. Further, the new mechanism does not necessitate any ‘smart decision-making’ by the pertinent redox isozyme(s). For LDH, the new theory explains its multimeric nature, non-variant structure of the isozymes’ active sites and accounts for why lactate is transported to the liver for further utilization within the physiological purview of Cori cycle. The theoretical insights, in silico evidence and analyses of literature herein also enrich our understanding of ‘lactic acidosis’ (in clinical context), Warburg effect and approach for cancer therapy.

scholarly journals Dual Targeting of the Warburg Effect with a Glucose-Conjugated Lactate Dehydrogenase Inhibitor

ChemBioChem ◽  
2013 ◽  
Vol 14 (17) ◽  
pp. 2263-2267 ◽  
Author(s):  
Emilia C. Calvaresi ◽  
Carlotta Granchi ◽  
Tiziano Tuccinardi ◽  
Valeria Di Bussolo ◽  
Robert W. Huigens ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Warburg Effect ◽  
Dual Targeting ◽  
The Warburg Effect ◽  
Lactate Dehydrogenase Inhibitor

Abstract 243: The Role of Reactive Oxygen Species in Hyperglycemia-Induced Attenuation of Anesthetic Preconditioning in Induced Pluripotent Stem Cell-Derived Cardiomyocytes

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Scott Canfield ◽  
Danielle Twaroski ◽  
Xiaowen Bai ◽  
Chika Kikuchi ◽  
Zeljko J Bosnjak
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Membrane Potential ◽  
Lactate Dehydrogenase ◽  
Mitochondrial Membrane ◽  
Oxygen Species ◽  
Anesthetic Preconditioning ◽  
Induced Pluripotent ◽  
Type 2 Diabetic

Anesthetic Preconditioning (APC) protects the myocardium from ischemia/reperfusion injury. The cardioprotective effects of APC is diminished or even eliminated in individuals with diabetes mellitus and/or hyperglycemia. The development of patient-specific induced pluripotent stem cells and their differentiation capability has provided us with an in vitro model to study the inefficiency of APC in these individuals.To investigate the underlying mechanisms involved in the attenuation of APC in both diabetic individuals and in hyperglycemia we utilized cardiomyocytes derived from Type 2 diabetic patient and healthy individual iPSCs, (T2DM-iPSCs and N-iPSCs, respectively). Contracting cardiomyocytes were dissociated and selected by the expression of green fluorescent protein under the transcriptional control of myosin light chain-2v. Cardiomyocytes were exposed to varying glucose concentrations (5, 11, and 25 mM). Lactate dehydrogenase (LDH) release was measured using a colorimetric cytotoxicity assay kit and read spectrophotometrically. Mitochondrial membrane potential and reactive oxygen species (ROS) generation were measured with confocal microscopy. APC reduced oxidative stress-induced lactate dehydrogenase (LDH) release in cardiomyocytes derived from both N-iPSCs- and T2DM-iPSCs in 5 and 11 mM glucose concentrations, but not in 25 mM glucose. Baseline membrane potential was similar between non-diabetic- and Type 2 diabetic-derived cardiomyocytes; however 25 mM glucose hyperpolarized the mitochondrial membrane potential. T2DM-iPSC-derived cardiomyocytes had an increase in ROS baseline levels compared to N-iPSC-derived cardiomyocytes. Additionally, high glucose concentrations increased oxidative stress-induced ROS production compared to lower glucose conditions in both cell lines. Our preliminary data shows that high glucose generates excessive ROS and hyperpolarizes the mitochondrial membrane and may contribute to the inefficiency of diabetic and/or hyperglycemic individuals to be anesthetically preconditioned. By utilizing human iPSC-derived cardiomyocytes we can begin to understand the inability of hyperglycemic and diabetic individuals to be anesthetically preconditioned.

Effect of extracellular Mg2+ on ROS and Ca2+ accumulation during reoxygenation of rat cardiomyocytes

2001 ◽  
Vol 280 (1) ◽  
pp. H344-H353 ◽  
Author(s):  
Mohammad N. Sharikabad ◽  
Kirsten M. Østbye ◽  
Torstein Lyberg ◽  
Odd Brørs
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Flow Cytometry ◽  
Lactate Dehydrogenase ◽  
Superoxide Anion ◽  
Oxygen Species ◽  
No Donor ◽  
Rat Cardiomyocytes ◽  
Intracellular Ros ◽  
Ldh Release

The effects of Mg2+ on reactive oxygen species (ROS) and cell Ca2+ during reoxygenation of hypoxic rat cardiomyocytes were studied. Oxidation of 2′,7′-dichlorodihydrofluorescein (DCDHF) to dichlorofluorescein (DCF) and of dihydroethidium (DHE) to ethidium (ETH) within cells were used as markers for intracellular ROS levels and were determined by flow cytometry. DCDHF/DCF is sensitive to H2O2 and nitric oxide (NO), and DHE/ETH is sensitive to the superoxide anion (O2 −·), respectively. Rapidly exchangeable cell Ca2+ was determined by 45Ca2+uptake. Cells were exposed to hypoxia for 1 h and reoxygenation for 2 h. ROS levels, determined as DCF fluorescence, were increased 100–130% during reoxygenation alone and further increased 60% by increasing extracellular Mg2+concentration to 5 mM at reoxygenation. ROS levels, measured as ETH fluorescence, were increased 16–24% during reoxygenation but were not affected by Mg2+. Cell Ca2+ increased three- to fourfold during reoxygenation. This increase was reduced 40% by 5 mM Mg2+, 57% by 10 μM 3,4-dichlorobenzamil (DCB) (inhibitor of Na+/Ca2+ exchange), and 75% by combining Mg2+ and DCB. H2O2 (25 and 500 μM) reduced Ca2+ accumulation by 38 and 43%, respectively, whereas the NO donor S-nitroso- N-acetyl-penicillamine (1 mM) had no effect. Mg2+ reduced hypoxia/reoxygenation-induced lactate dehydrogenase (LDH) release by 90%. In conclusion, elevation of extracellular Mg2+ to 5 mM increased the fluorescence of the H2O2/NO-sensitive probe DCF without increasing that of the O2 −·-sensitive probe ETH, reduced Ca2+ accumulation, and decreased LDH release during reoxygenation of hypoxic cardiomyocytes. The reduction in LDH release, reflecting the protective effect of Mg2+, may be linked to the effect of Mg2+ on Ca2+ accumulation and/or ROS levels.

scholarly journals Identification of different oxygen species in oxide nanostructures with 17O solid-state NMR spectroscopy

2015 ◽  
Vol 1 (1) ◽  
pp. e1400133 ◽  
Author(s):  
Meng Wang ◽  
Xin-Ping Wu ◽  
Sujuan Zheng ◽  
Li Zhao ◽  
Lei Li ◽  
...  
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Strong Dependence ◽  
Critical Role ◽  
Oxygen Species ◽  
Structure Property ◽  
Diverse Range ◽  
Oxygen Ions ◽  
Surface Sites ◽  
Nanostructured Oxides

Nanostructured oxides find multiple uses in a diverse range of applications including catalysis, energy storage, and environmental management, their higher surface areas, and, in some cases, electronic properties resulting in different physical properties from their bulk counterparts. Developing structure-property relations for these materials requires a determination of surface and subsurface structure. Although microscopy plays a critical role owing to the fact that the volumes sampled by such techniques may not be representative of the whole sample, complementary characterization methods are urgently required. We develop a simple nuclear magnetic resonance (NMR) strategy to detect the first few layers of a nanomaterial, demonstrating the approach with technologically relevant ceria nanoparticles. We show that the 17O resonances arising from the first to third surface layer oxygen ions, hydroxyl sites, and oxygen species near vacancies can be distinguished from the oxygen ions in the bulk, with higher-frequency 17O chemical shifts being observed for the lower coordinated surface sites. H217O can be used to selectively enrich surface sites, allowing only these particular active sites to be monitored in a chemical process. 17O NMR spectra of thermally treated nanosized ceria clearly show how different oxygen species interconvert at elevated temperature. Density functional theory calculations confirm the assignments and reveal a strong dependence of chemical shift on the nature of the surface. These results open up new strategies for characterizing nanostructured oxides and their applications.

scholarly journals Study on Oxidative Metabolic Changes to Differentiate Exudative from Transudative Pleural Effusions

1970 ◽  
Vol 1 (1) ◽  
pp. 38-43
Author(s):  
V Narsimha Reddy ◽  
V Anil Kumar ◽  
M Srinivas ◽  
V Narayana Reddy
Keyword(s):  
Oxidative Stress ◽  
Lactate Dehydrogenase ◽  
Pleural Fluid ◽  
Total Protein ◽  
Biochemical Parameters ◽  
Oxygen Species ◽  
Pleural Effusions ◽  
Glucose Levels ◽  
Protein Serum ◽  
Serum Ratio

The purpose of this present study was to differentiate transudates and exudates in pleural effusions. Oxidative stress has been associated with various respiratory disorders. Ninety patients of pleural effusions of diverse etiologies were participated in this study. Subjects underwent diagnostic thoracentesis and standard biochemical parameters (total protein, lactate dehydrogenase, glucose, MDA levels) were measured in pleural fluid and serum. MDA, total protein, lactate dehydrogenase (LDH), glucose levels in plural fluid were higher in exudates compared to transudates (p < 0.001). Total protein pleural fluid/ total protein serum ratio, LDH pleural fluid/LDH serum ratio and MDA pleural fluid/MDA serum ratio were raised in exudates compared to transudates (p < 0.001). The present study showed that oxidative stress was more in exudates compared to transudates, probably due to the production of reactive oxygen species and it may serve as a marker for differentiation between transudates and exudates in clinical practice. Key Words: Exudates, Melondialdehyde, Oxidative Stress, Pleural Effusion, Transudates    doi:10.3329/sjps.v1i1.1806 S. J. Pharm. Sci. 1(1&2): 38-43

scholarly journals Re-evaluation of the glycerol-3-phosphate dehydrogenase/l-lactate dehydrogenase enzyme system. Evidence against the direct transfer of NADH between active sites

1991 ◽  
Vol 278 (3) ◽  
pp. 875-881 ◽  
Author(s):  
S P J Brooks ◽  
K B Storey
Keyword(s):  
Lactate Dehydrogenase ◽  
Active Sites ◽  
Reaction Rate ◽  
Experimental Results ◽  
Transfer Model ◽  
Rabbit Muscle ◽  
Direct Transfer ◽  
Theoretical Predictions ◽  
Glycerol 3 Phosphate Dehydrogenase

An investigation of the direct transfer of metabolites from rabbit muscle L-lactate dehydrogenase (LDH, EC 1.1.1.27) to glycerol-3-phosphate dehydrogenase (GPDH, EC 1.1.1.8) revealed discrepancies between theoretical predictions and experimental results. Measurements of the GPDH reaction rate at a fixed NADH concentration and in the presence of increasing LDH concentrations gave experimental results similar to those previously obtained by Srivastava, Smolen, Betts, Fukushima, Spivey & Bernhard [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 6464-6468]. However, a mathematical solution of the direct-transfer-mechanism equations as described by Srivastava et al. (1989) showed that the direct-transfer model did not adequately describe the experimental behaviour of the reaction rate at increasing LDH concentrations. In addition, experiments designed to measure the formation of an LDH4.NADH.GPDH2 complex, predicted by the direct-transfer model, indicated that no significant formation of tertiary complex occurred. An examination of other kinetic models, developed to describe the LDH/GPDH/NADH system better, revealed that the experimental results may be best explained by assuming that free NADH, and not E1.NADH, is the sole substrate for GPDH. These results suggest that direct transfer of NADH between rabbit muscle LDH and GPDH does not occur in vitro.

scholarly journals The identification of intermediates in the reaction of pig heart lactate dehydrogenase with its substrates

1974 ◽  
Vol 139 (3) ◽  
pp. 677-697 ◽  
Author(s):  
J. R. Whitaker ◽  
D. W. Yates ◽  
N. G. Bennett ◽  
J. J. Holbrook ◽  
H. Gutfreund
Keyword(s):  
Steady State ◽  
Lactate Dehydrogenase ◽  
Rate Constant ◽  
Active Sites ◽  
Phase 1 ◽  
Lactate Concentration ◽  
Phenol Red ◽  
Phase 2 ◽  
Protein Fluorescence ◽  
Rapid Formation

Pig heart lactate dehydrogenase was studied in the direction of pyruvate and NADH formation by recording rapid changes in extinction, proton concentration, nucleotide fluorescence and protein fluorescence. Experiments measuring extinction changes show that there is a very rapid formation of NADH within the first millisecond and that the amplitude of this phase (phase 1) increases threefold over the pH range 6–8. A second transient rate (phase 2) can also be distinguished (whose rate is pH-dependent), followed by a steady-state rate (phase 3) of NADH production. The sum of the amplitudes of the first two phases corresponds to 1mol of NADH produced/mol of active sites of lactate dehydrogenase. Experiments that measured the liberation of protons by using Phenol Red as an indicator show that no proton release occurs during the initial very rapid formation of NADH (phase 1), but protons are released during subsequent phases of NADH production. Fluorescence experiments help to characterize these phases, and show that the very rapid phase 1 corresponds to the establishment of an equilibrium between ENADLactate ⇌ H+ENADHPyruvate. This equilibrium can be altered by changing lactate concentration or pH, and the H+ENADHPyruvate species formed has very low nucleotide fluorescence and quenched protein fluorescence. Phase 2 corresponds to the dissociation of pyruvate and a proton from the complex with a rate constant of 1150s-1. The observed rate constant is slower than this and is proportional to the position of the preceding equilibrium. The ENADH formed has high nucleotide fluorescence and quenched protein fluorescence. The reaction, which is rate-limiting during steady-state turnover, must then follow this step and be involved with dissociation of NADH from the enzyme or some conformational change immediately preceding dissociation. Several inhibitory complexes have also been studied including ENAD+Oxamate and ENADHOxamate' and the abortive ternary complex ENADHLactate. The rate of NADH dissociation from the enzyme was measured and found to be the same whether measured by ligand displacement or by relaxation experiments. These results are discussed in relation to the overall mechanism of lactate dehydrogenase turnover and the independence of the four binding sites in the active tetramer.

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