24 results match your criteria murburn

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Interaction of membrane-embedded cytochrome b-complexes with quinols: Classical Q-cycle and murburn model.

Cell Biochem Funct 2022 Jan 13. Epub 2022 Jan 13.

Karel de Grote University College, Antwerp University Association, Campus Hoboken, Hoboken, Belgium.

We recently proposed a diffusible reactive (oxygen) species (DRS/DROS) based function for cytochrome b complexes (CBC) and quinones (Q)/quinols (QH ) in the murburn model of bioenergetics. This proposal is in direct conflict with the classical purview of Q-cycle. Via extensive analyses of the structure-function correlations of membrane-quinones/quinols and proteins, we present qualitative and quantitative arguments to infer that the classical model cannot explain the energetics, kinetics, mechanism and probabilistic considerations. Read More

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January 2022

Murburn precepts for lactic-acidosis, Cori cycle, and Warburg effect: Interactive dynamics of dehydrogenases, protons, and oxygen.

J Cell Physiol 2021 Dec 20. Epub 2021 Dec 20.

Department of Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, Kerala, India.

It is unresolved why lactate is transported to the liver for further utilization within the physiological purview of Cori cycle, when muscles have more lactate dehydrogenase (LDH) than liver. We point out that the answer lies in thermodynamics/equilibriums. While the utilization of NADH for the reduction of pyruvate to lactate can be mediated via the classical mechanism, the oxidation of lactate (with/without the uphill reduction of NAD ) necessitates alternative physiological approaches. Read More

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December 2021

Why do cells need oxygen? Insights from mitochondrial composition and function.

Cell Biol Int 2021 Dec 17. Epub 2021 Dec 17.

Industrial Sciences and Technology, Karel de Grote-Hogeschool, Association University and High Schools Antwerp, Antwerpen, Belgium.

Mitochondrial membrane-embedded redox proteins are classically perceived as deterministic "electron transport chain" (ETC) arrays cum proton pumps; and oxygen is seen as an "immobile terminal electron acceptor." This is untenable because: (1) there are little free protons to be pumped out of the matrix; (2) proton pumping would be highly endergonic; (3) ETC-chemiosmosis-rotary ATP synthesis proposal is "irreducibly complex"/"non-evolvable" and does not fit with mitochondrial architecture or structural/distribution data of the concerned proteins/components; (4) a plethora of experimental observations do not conform to the postulates/requisites; for example, there is little evidence for viable proton-pumps/pH-gradient in mitochondria, trans-membrane potential (TMP) is non-fluctuating/non-trappable, oxygen is seen to give copious "diffusible reactive (oxygen) species" (DRS/DROS) in milieu, etc. Quite contrarily, the newly proposed murburn model's tenets agree with known principles of energetics/kinetics, and builds on established structural data and reported observations. Read More

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December 2021

Critical analysis of explanations for cellular homeostasis and electrophysiology from murburn perspective.

J Cell Physiol 2021 Sep 13. Epub 2021 Sep 13.

Department of Mechanical Engineering, Gifu University, Yanagido, Gifu City, Japan.

Pursuits in modern cellular electrophysiology are fraught with disagreements at a fundamental level. While the membrane theory of homeostasis deems the cell membrane and proteins embedded therein as the chief players, the association-induction (or sorption/bulk-phase) hypothesis considers the aqueous phase of dissolved proteins (cytoplasm/protoplasm) as the key determinant of cellular composition and ionic fluxes. In the first school of thought, trans-membrane potential (TMP) and selective ion pumps/channels are deemed as key operative principles. Read More

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September 2021

The murburn precepts for cellular ionic homeostasis and electrophysiology.

J Cell Physiol 2021 Aug 11. Epub 2021 Aug 11.

Department of Mechanical Engineering, Gifu University, Yanagido, Gifu, Japan.

Starting from the basic molecular structure and redox properties of its components, we build a macroscopic cellular electrophysiological model. We first present a murburn purview that could explain ion distribution in bulk-milieu/membrane-interface and support the origin of trans-membrane potential (TMP) in cells. In particular, the discussion focuses on how cells achieve disparity in the distribution of monovalent and divalent cations within (K  > Na  > Mg  > Ca ) and outside (Na  > K  > Ca  > Mg ). Read More

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Validating the predictions of murburn model for oxygenic photosynthesis: Analyses of ligand-binding to protein complexes and cross-system comparisons.

J Biomol Struct Dyn 2021 Jul 30:1-33. Epub 2021 Jul 30.

RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India.

In this second half of our treatise on oxygenic photosynthesis, we provide support for the murburn model of the light reaction of photosynthesis and ratify key predictions made in the first part. Molecular docking and visualization of various ligands of quinones/quinols (and their derivatives) with PS II/Cytochrome complexes did not support chartered 2e-transport role of quinols. A broad variety of herbicides did not show any affinity/binding-based rationales for inhibition of photosynthesis. Read More

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Structure-function correlations and system dynamics in oxygenic photosynthesis: classical perspectives and murburn precepts.

J Biomol Struct Dyn 2021 Jul 29:1-27. Epub 2021 Jul 29.

Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India.

Highlights: Contemporary beliefs on oxygenic photosynthesis are critiqued.Murburn model is suggested as an alternative explanation.In the new model, diffusible reactive species are the main protagonists. Read More

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The murburn precepts for aerobic respiration and redox homeostasis.

Prog Biophys Mol Biol 2021 Dec 10;167:104-120. Epub 2021 Jun 10.

Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, St. Institutskaya 3, 630090, Novosibirsk, Russia. Electronic address:

Murburn concept is a new perspective to metabolism which posits that certain redox enzymes/proteins mediate catalysis outside their active site, via diffusible reactive oxygen species (DROS, usually deemed as toxic wastes). We have recently questioned the proton-centric chemiosmotic rotary ATP synthesis (CRAS) explanation for mitochondrial oxidative phosphorylation (mOxPhos) and proposed an oxygen-centric murburn model in lieu. Herein, the chemical equations and thermodynamic foundations for this new model of mOxPhos are detailed. Read More

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December 2021

Mechanism of electron transfers mediated by cytochromes and in mitochondria and endoplasmic reticulum: classical and murburn perspectives.

J Biomol Struct Dyn 2021 May 17:1-18. Epub 2021 May 17.

Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala State, India.

We explore the mechanism of electron transfers mediated by cytochrome , a soluble protein involved in mitochondrial oxidative phosphorylation and cytochrome , a microsomal membrane protein acting as a redox aide in xenobiotic metabolism. We found minimal conservation in the sequence and surface amino acid residues of cytochrome proteins among divergent species. Therefore, we question the evolutionary logic for electron transfer (ET) occurring through affinity binding via recognition of specific surface residues/topography. Read More

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Hemoglobin catalyzes ATP-synthesis in human erythrocytes: a murburn model.

J Biomol Struct Dyn 2021 May 17:1-13. Epub 2021 May 17.

Satyamjayatu: The Science & Ethics Foundation, Kulappully, India.

Blood hemoglobin (Hb), known to transport oxygen, is the most abundant globular protein in humans. Erythrocytes have ∼10 M concentration of ATP in steady-state and we estimate that this high amounts cannot be formed from 10 - 10 M levels of precursors via substrate-level phosphorylation of glycolysis. To account for this discrepancy, we propose that Hb serves as a 'murzyme' (a redox enzyme working along the principles of murburn concept), catalyzing the synthesis of the major amounts of ATP found in erythrocytes. Read More

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Murburn Precepts for Cytochrome P450 Mediated Drug/Xenobiotic Metabolism and Homeostasis.

Curr Drug Metab 2021 ;22(4):315-326

Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala-679122, India.

Aims: We aim to demonstrate why deeming diffusible reactive oxygen species (DROS) as toxic wastes do not afford a comprehensive understanding of cytochrome P450 mediated microsomal xenobiotic metabolism (mXM).

Background: Current pharmacokinetic investigations consider reactive oxygen species formed in microsomal reactions as toxic waste products, whereas our works (Manoj et al., 2016) showed that DROS are the reaction mainstay in cytochrome P450 mediated metabolism and that they play significant roles in explaining several unexplained physiologies. Read More

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December 2021

Are plastocyanin and ferredoxin specific electron carriers or generic redox capacitors? Classical and murburn perspectives on two photosynthetic proteins.

J Biomol Struct Dyn 2020 Oct 19:1-15. Epub 2020 Oct 19.

Department of Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, India.

In the light reaction of oxygenic photosynthesis, plastocyanin (PC) and ferredoxins (Fd) are small/diffusible redox-active proteins playing key roles in electron transfer/transport phenomena. In the Z-scheme mechanistic purview, they are considered as specific affinity binding-based electron-relay agents, linking the functions of Cytochrome (Cyt. ), Photosystem I (PS I) and Fd:NADPH oxidoreductase (FNR). Read More

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October 2020

What is the Role of Lipid Membrane-embedded Quinones in Mitochondria and Chloroplasts? Chemiosmotic Q-cycle versus Murburn Reaction Perspective.

Cell Biochem Biophys 2021 Mar 29;79(1):3-10. Epub 2020 Sep 29.

Department of Biotechnology, Vignan's Foundation for Science, Technology & Research, Vadlamudi, Guntur, 522213, India.

Quinones are found in the lipid membranes of prokaryotes like E. coli and cyanobacteria, and are also abundant in eukaryotic mitochondria and chloroplasts. They are intricately involved in the reaction mechanism of redox phosphorylations. Read More

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Chemiosmotic misunderstandings.

Authors:
Pedro J Silva

Biophys Chem 2020 09 27;264:106424. Epub 2020 Jun 27.

FP-ENAS/Fac. de Ciências da Saúde, Universidade Fernando Pessoa, Porto, Portugal; [email protected], BioSIM, Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal. Electronic address:

Recent publications have questioned the appropriateness of the chemiosmotic theory, a key tenet of modern bioenergetics originally described by Mitchell and since widely improved upon and applied. In one of them, application of Gauss' law to a model charge distribution in mitochondria was argued to refute the possibility of ATP generation through H movement in the absence of a counterion, whereas a different author advocated, for other reasons, the impossibility of chemiosmosis and proposed that a novel energy-generation scheme (referred to as "murburn") relying on superoxide-catalyzed (or superoxide-promoted) ADP phosphorylation would operate instead. In this letter, those proposals are critically examined and found to be inconsistent with established experimental data and new theoretical calculations. Read More

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September 2020

Acute toxicity of cyanide in aerobic respiration: Theoretical and experimental support for murburn explanation.

Biomol Concepts 2020 Mar 17;11(1):32-56. Epub 2020 Mar 17.

Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India-781039.

The inefficiency of cyanide/HCN (CN) binding with heme proteins (under physiological regimes) is demonstrated with an assessment of thermodynamics, kinetics, and inhibition constants. The acute onset of toxicity and CN's mg/Kg LD50 (μM lethal concentration) suggests that the classical hemeFe binding-based inhibition rationale is untenable to account for the toxicity of CN. In vitro mechanistic probing of CN-mediated inhibition of hemeFe reductionist systems was explored as a murburn model for mitochondrial oxidative phosphorylation (mOxPhos). Read More

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Acute toxicity of cyanide in aerobic respiration: Theoretical and experimental support for murburn explanation.

Biomol Concepts 2020 03 17;11(1):32-56. Epub 2020 Mar 17.

Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India-781039.

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Classical and murburn explanations for acute toxicity of cyanide in aerobic respiration: A personal perspective.

Toxicology 2020 02 30;432:152369. Epub 2020 Jan 30.

Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala, 679122, India.

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February 2020

Murburn concept: a paradigm shift in cellular metabolism and physiology.

Biomol Concepts 2020 Jan 22;11(1):7-22. Epub 2020 Jan 22.

Satyamjayatu: The Science & Ethics Foundation,Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala,India-679122.

Two decades of evidence-based exploratory pursuits in heme-flavin enzymology led to the formulation of a new biological electron/moiety transfer paradigm, called murburn concept. Murburn is a novel literary abstraction from "mured burning" or "mild unrestricted burning". This concept was invoked to explain the longstanding conundrum of maverick physiological dose responses and also applied to remodel the prevailing understanding of drug metabolism and cellular respiration. Read More

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January 2020

Murburn concept: a paradigm shift in cellular metabolism and physiology.

Biomol Concepts 2020 Jan 22;11(1):7-22. Epub 2020 Jan 22.

Satyamjayatu: The Science & Ethics Foundation,Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala, India-679122.

Two decades of evidence-based exploratory pursuits in heme-flavin enzymology led to the formulation of a new biological electron/moiety transfer paradigm, called murburn concept. Murburn is a novel literary abstraction from " ed ing" or " ild n estricted ing". This concept was invoked to explain the longstanding conundrum of maverick physiological dose responses and also applied to remodel the prevailing understanding of drug metabolism and cellular respiration. Read More

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January 2020

Refutation of the cation-centric torsional ATP synthesis model and advocating murburn scheme for mitochondrial oxidative phosphorylation.

Biophys Chem 2020 02 18;257:106278. Epub 2019 Nov 18.

Satyamjayatu: The Science & Ethics Foundation, Shoranur-2 PO, Palakkad District, Kerala 679122, India. Electronic address:

The acclaimed explanation for mitochondrial oxidative phosphorylation (mOxPhos) is a proton or cation centric scheme. Such ideas were recently disclaimed and in lieu, an evidence-based oxygen-centric explanation, murburn concept, was proposed. The new understanding vouches for catalytic roles of diffusible reactive oxygen species (DROS). Read More

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February 2020

Chemiosmotic and murburn explanations for aerobic respiration: Predictive capabilities, structure-function correlations and chemico-physical logic.

Arch Biochem Biophys 2019 11 14;676:108128. Epub 2019 Oct 14.

Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, St. Institutskaya 3, 630090, Novosibirsk, Russia. Electronic address:

Since mid-1970s, the proton-centric proposal of 'chemiosmosis' became the acclaimed explanation for aerobic respiration. Recently, significant theoretical and experimental evidence were presented for an oxygen-centric 'murburn' mechanism of mitochondrial ATP-synthesis. Herein, we compare the predictive capabilities of the two models with respect to the available information on mitochondrial reaction chemistry and the membrane proteins' structure-function correlations. Read More

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November 2019

Aerobic respiration: proof of concept for the oxygen-centric murburn perspective.

J Biomol Struct Dyn 2019 10 8;37(17):4542-4556. Epub 2019 Jan 8.

Department of Biotechnology, Indian Institute of Technology Guwahati , Guwahati , Assam, India.

The inner mitochondrial membrane protein complexes (I-V) and prokaryotic respiratory machinery are examined for a deeper understanding of their structure-function correlations and dynamics. analysis of the structure of complexes I-IV, docking studies and erstwhile literature confirm that they carry sites which are in close proximity to DROS (diffusible reactive oxygen species) generating redox centers. These findings provide supportive evidence for the newly proposed oxygen-centric chemical-coupling mechanism (murburn concept), wherein DROS catalyzes the esterification of inorganic phosphate to ADP. Read More

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October 2019

Murburn Concept: A Molecular Explanation for Hormetic and Idiosyncratic Dose Responses.

Dose Response 2018 Apr-Jun;16(2):1559325818774421. Epub 2018 May 9.

Satyamjayatu: The Science and Ethics Foundation, Kerala, India.

Recently, electron transfers and catalyses in a bevy of redox reactions mediated by hemeproteins were explained by murburn concept. The term "murburn" is abstracted from "" or "" and connotes a novel "" interaction paradigm. Quite unlike the genetic regulations and protein-level affinity-based controls that govern order and specificity/selectivity in conventional treatments, murburn concept is based on stochastic/thermodynamic regulatory principles. Read More

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Functioning of Microsomal Cytochrome P450s: Murburn Concept Explains the Metabolism of Xenobiotics in Hepatocytes.

Front Pharmacol 2016 23;7:161. Epub 2016 Jun 23.

REDOx Lab, PSG Institute of Advanced Studies Coimbatore, India.

Using oxygen and NADPH, the redox enzymes cytochrome P450 (CYP) and its reductase (CPR) work in tandem to carry out the phase I metabolism of a vast majority of drugs and xenobiotics. As per the erstwhile understanding of the catalytic cycle, binding of the substrate to CYP's heme distal pocket allows CPR to pump electrons through a CPR-CYP complex. In turn, this trigger (a thermodynamic push of electrons) leads to the activation of oxygen at CYP's heme-center, to give Compound I, a two-electron deficient enzyme reactive intermediate. Read More

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