Regulation of succinate dehydrogenase and tautomerization of oxaloacetate

Vinogradov, Andrei D.; Kotlyar, Alexander; Burov, Victor I.; Belikova, Yuliya O.

doi:10.1016/0065-2571(89)90076-9

Cited by 20 publications

(14 citation statements)

References 11 publications

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“…The succinate oxidation rate is maximum when the succinate/fumarate ratio is high and the quinol/quinone ratio is low. The turnover in the forward direction predicted by the model is in the range previously determined by other groups [45][46][47]. The model also predicts that enzyme's turnover in the reverse direction is approximately double that of the forward direction.…”

Section: A B Csupporting

confidence: 74%

Analysis of Mammalian Succinate Dehydrogenase Kinetics and Reactive Oxygen Species Production

Manhas

Duong

Lee

et al. 2019

Preprint

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Succinate dehydrogenase is an inner mitochondrial membrane protein complex that links the tricarboxylic acid cycle to the electron transport system. It catalyzes the reaction between succinate and ubiquinone to produce fumarate and ubiquinol. In addition, it can produce significant amounts of superoxide and hydrogen peroxide under the right conditions. While the flavin adenine dinucleotide (FAD) is the putative site of reactive oxygen species production, free radical production from other sites are less certain. Herein, we developed a computational model to analyze free radical production data from complex II and identify the mechanism of superoxide and hydrogen peroxide production. The model includes the major redox centers consisting of the FAD, three iron-sulfur clusters, and a transiently catalytic bound semi quinone. The model consists of five-states that represent oxidation status of the enzyme complex. Each step in the reaction scheme is thermodynamically constrained, and transitions between each state involve either one-electron or two-electron redox reactions. The model parameters were simultaneously fit using data consisting of enzyme kinetics and free radical production rates under a range of conditions. In the absence of respiratory chain inhibitors, model analysis revealed that the 3Fe-4S iron-sulfur cluster is the primary source of superoxide production followed by the FAD radical. However, when the quinone reductase site of complex II is inhibited or the quinone pool is highly reduced, superoxide production from the FAD site dominates at low succinate concentrations. In addition, hydrogen peroxide formation from the complex is only significant when these one of these conditions is met and the fumarate concentrations is in the low micromolar range. From the model simulations, the redox state of the quinone pool was found to be the primary determinant of free radical production from complex II. This study highlights the importance of evaluating enzyme kinetics and associated side-reactions in a consistent, quantitative and biophysical detailed manner. By incorporating the results from a diverse set of experiments, this computational approach can be used to interpret and explain key differences among the observations from a single, unified perspective. QH SUC H O O J J J J •-= --

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Section: A B Csupporting

confidence: 74%

Analysis of Mammalian Succinate Dehydrogenase Kinetics and Reactive Oxygen Species Production

Manhas

Duong

Lee

et al. 2019

Preprint

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“…Electrons entering the FAD site, however, can be blocked by other non-SDH dicarboxylate substrates that are present in the mitochondrial matrix including malonate, malate and oxaloacetate. In addition, oxaloacetate causes the enzyme to enter an inactive state (39). Quinol oxidation at the Q p site is another way by which SDH is reduced.…”

Section: Resultsmentioning

confidence: 99%

Computationally modeling mammalian succinate dehydrogenase kinetics identifies the origins and primary determinants of ROS production

Manhas

Duong

Lee

et al. 2020

Journal of Biological Chemistry

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Succinate dehydrogenase (SDH) is an inner mitochondrial membrane protein complex that links the Krebs cycle to the electron transport system. It can produce significant amounts of superoxide (O2.-) and hydrogen peroxide (H2O2); however, the precise mechanisms are unknown. This fact hinders the development of next-generation antioxidant therapies targeting mitochondria. To help address this problem, we developed a computational model to analyze and identify the kinetic mechanism of O2.- and H2O2 production by SDH. Our model includes the major redox centers in the complex, namely FAD, three iron-sulfur clusters, and a transiently bound semiquinone. Oxidation state transitions involve a one- or two-electron redox reaction, each being thermodynamically constrained. Model parameters were simultaneously fit to many data sets using a variety of succinate oxidation and free radical production data. In the absence of respiratory chain inhibitors, model analysis revealed the 3Fe-4S iron-sulfur cluster as the primary O2.- source. However, when the quinone reductase site is inhibited or the quinone pool is highly reduced, O2.- is generated primarily by the FAD. In addition, H2O2 production is only significant when the enzyme is fully reduced, and fumarate is absent. Our simulations also reveal that the redox state of the quinone pool is the primary determinant of free radical production by SDH. In this study, we showed the importance of analyzing enzyme kinetics and associated side-reactions in a consistent, quantitative, and biophysically detailed manner using a diverse set of experimental data to interpret and explain experimental observations from a unified perspective.

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“…2) [53]. enol‐OAA is a high affinity and very slow dissociating inhibitor of SDH ( K d ~ 10 −8 m , K off = 0.02 min −1 ) [52,54‐56]. In vitro , purified SDH catalyzes < 10 turnovers with malate as the substrate before the enzyme becomes completely inactivated due to tightly bound enol‐OAA [57].…”

Section: Promiscuous Succinic Dehydrogenase Activity Results In Enol‐mentioning

confidence: 99%

“…Proteins with OAA enol‐keto tautomerase (OAT, EC 5.3.2.2) activity from several prokaryotes and eukaryotes have been reported [58,61,62]. It was demonstrated that OAT enzymes, in the presence of a (keto) OAA‐metabolizing enzyme, protect SDH from enol‐OAA inactivation that would otherwise occur as a result of promiscuous malate oxidation [56]. Interestingly, in mammals, the TCA cycle hydro‐lyase enzyme aconitase has OAT activity [63], while in E. coli , another TCA cycle hydro‐lyase enzyme fumarate hydratase (FH) has OAT activity [62].…”

Section: Promiscuous Succinic Dehydrogenase Activity Results In Enol‐mentioning

confidence: 99%

“…At the time OAT enzymes were being characterized, they were mainly discussed in terms of TCA cycle regulation [56]. While an enzyme that removes a strong inhibitor of the TCA cycle is a potential regulator, the more likely scenario is that OAT activity is necessary to remove a toxic metabolite whose formation is inevitable yet serves no particular purpose.…”

Section: Promiscuous Succinic Dehydrogenase Activity Results In Enol‐mentioning

confidence: 99%

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Enzyme promiscuity, metabolite damage, and metabolite damage control systems of the tricarboxylic acid cycle

Niehaus

Hillmann

2020

The FEBS Journal

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Promiscuous enzymes and spontaneous chemical reactions can convert normal cellular metabolites into noncanonical or damaged metabolites. These damaged metabolites can be a useless drain on metabolism and may be inhibitory and/or reactive, sometimes leading to toxicity. Thus, mechanisms to prevent metabolite damage from occurring (metabolite damage preemption) or to convert damaged metabolites back to physiological forms (metabolite repair) are essential for sustained operation of metabolic networks. Some iconic examples of metabolite damage and its repair or preemption are associated with the tricarboxylic acid (TCA) cycle, and other metabolite damage control systems are likely to exist here due to the inherent promiscuity of TCA cycle enzymes and reactivity of TCA cycle intermediates. Here, we review known metabolite damage reactions and metabolite damage control systems associated with the TCA cycle. This includes a previously unrecognized metabolite damage control system – an oxaloacetate (OAA) enol‐keto tautomerase activity that is ‘built‐in’ to the TCA cycle. This activity is required to remove the highly inhibitory enol form of OAA and is likely to be critical for TCA cycle operation. By cataloging these instances, we show that metabolite damage and its repair or preemption is a prevalent feature of the TCA cycle and suggest many more metabolite damage control systems are likely to exist.

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Regulation of succinate dehydrogenase and tautomerization of oxaloacetate

Cited by 20 publications

References 11 publications

Analysis of Mammalian Succinate Dehydrogenase Kinetics and Reactive Oxygen Species Production

Analysis of Mammalian Succinate Dehydrogenase Kinetics and Reactive Oxygen Species Production

Computationally modeling mammalian succinate dehydrogenase kinetics identifies the origins and primary determinants of ROS production

Enzyme promiscuity, metabolite damage, and metabolite damage control systems of the tricarboxylic acid cycle

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