1
|
Kuzmiak-Glancy S, Glancy B, Kay MW. Ischemic damage to every segment of the oxidative phosphorylation cascade elevates ETC driving force and ROS production in cardiac mitochondria. Am J Physiol Heart Circ Physiol 2022; 323:H499-H512. [PMID: 35867709 PMCID: PMC9448280 DOI: 10.1152/ajpheart.00129.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myocardial ischemia has long-lasting negative impacts on cardiomyocyte mitochondrial ATP production. However, the location(s) of damage to the oxidative phosphorylation pathway responsible for altered mitochondrial function is unclear. Mitochondrial reactive oxygen species (ROS) production increases following ischemia, but the specific factors controlling this increase are unknown. To determine how ischemia affects the mitochondrial energy conversion cascade and ROS production, mitochondrial driving forces [redox potential and membrane potential (ΔΨ)] were measured at resting, intermediate, and maximal respiration rates in mitochondria isolated from rat hearts after 60 min of control flow (control) or no-flow ischemia (ischemia). The effective activities of the dehydrogenase enzymes, the electron transport chain (ETC), and ATP synthesis and transport were computed using the driving forces and flux. Ischemia lowered maximal mitochondrial respiration rates and diminished the responsiveness of respiration to both redox potential and ΔΨ. Ischemia decreased the activities of every component of the oxidative phosphorylation pathway: the dehydrogenase enzymes, the ETC, and ATP synthesis and transport. ROS production was linearly related to driving force down the ETC; however, ischemia mitochondria demonstrated a greater driving force down the ETC and higher ROS production. Overall, results indicate that ischemia ubiquitously damages the oxidative phosphorylation pathway, reduces mitochondrial sensitivity to driving forces, and augments the propensity for electrons to leak from the ETC. These findings underscore that strategies to improve mitochondrial function following ischemia must target the entire mitochondrial energy conversion cascade. NEW & NOTEWORTHY This integrative analysis is the first to assess how myocardial ischemia alters the mitochondrial driving forces and the degree to which individual segments of the mitochondrial energy transduction pathway contribute to diminished function following ischemia. This investigation demonstrates that increased reactive oxygen species production following ischemia is related to a lower effective activity of the electron transport chain and a greater driving force down the electron transport chain.
Collapse
Affiliation(s)
- Sarah Kuzmiak-Glancy
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD, United States
| | - Brian Glancy
- Laboratory of Muscle Energetics, National Heart, Lung, and Blood Institute and National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| |
Collapse
|
2
|
Finlayson J, Barakati N, Langlais PR, Funk J, Zapata Bustos R, Coletta DK, Luo M, Willis WT, Mandarino LJ. Site-specific acetylation of adenine nucleotide translocase 1 at lysine 23 in human muscle. Anal Biochem 2021; 630:114319. [PMID: 34332952 DOI: 10.1016/j.ab.2021.114319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/14/2021] [Accepted: 07/28/2021] [Indexed: 12/01/2022]
Abstract
Evidence suggests acetylation of human adenine nucleotide translocase 1 (ANT1) at lysine 23 (Lys23) reduces binding of ADP. Lys23 contributes to the positive charge that facilitates this interaction. This study was undertaken to characterize ANT1 abundance and acetylation by a novel method using small amounts of human skeletal muscle biopsies. Lysates of whole muscle or mitochondria from the same tissue were prepared from needle biopsies of vastus lateralis muscle of healthy volunteers. Lysed proteins were resolved on gels, the section containing ANT1 (surrounding 30 Kd) was excised, digested with trypsin, spiked with labeled unacetylated and acetylated synthetic standard peptides and analyzed by mass spectrometry. Natural logarithm transformation of data linearized ion intensities over a 10-fold range of peptide mass. Coefficients of variation ranged from 7 to 30% for ANT1 abundance and Lys23 acetylation. In three volunteers, ANT1 content was 8.36 ± 0.33 nmol/g wet weight muscle and 0.64 ± 0.05 nmol/mg mitochondria, so mitochondrial content was 13.3 ± 2.4 mg mitochondria per gram muscle. Acetylation of Lys23 averaged 14.3 ± 4.2% and 4.87 ± 1.84% in whole muscle and mitochondria, respectively. This assay makes it possible to assess effects of acetylation on the function of ANT1 in human muscle.
Collapse
Affiliation(s)
- Jean Finlayson
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA
| | - Neusha Barakati
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA
| | - Paul R Langlais
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA
| | - Janet Funk
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA
| | - Rocio Zapata Bustos
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA
| | - Dawn K Coletta
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA; Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Moulun Luo
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA
| | - Wayne T Willis
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA
| | - Lawrence J Mandarino
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, AZ, USA; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona Health Science, Tucson, AZ, USA.
| |
Collapse
|
3
|
Willis W, Willis E, Kuzmiak-Glancy S, Kras K, Hudgens J, Barakati N, Stern J, Mandarino L. Oxidative phosphorylation K 0.5ADP in vitro depends on substrate oxidative capacity: Insights from a luciferase-based assay to evaluate ADP kinetic parameters. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148430. [PMID: 33887230 DOI: 10.1016/j.bbabio.2021.148430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/30/2021] [Accepted: 04/07/2021] [Indexed: 12/21/2022]
Abstract
The K0.5ADP of oxidative phosphorylation (OxPhos) identifies the cytosolic ADP concentration which elicits one-half the maximum OxPhos rate. This kinetic parameter is commonly measured to assess mitochondrial metabolic control sensitivity. Here we describe a luciferase-based assay to evaluate the ADP kinetic parameters of mitochondrial ATP production from OxPhos, adenylate kinase (AK), and creatine kinase (CK). The high sensitivity, reproducibility, and throughput of the microplate-based assay enabled a comprehensive kinetic assessment of all three pathways in mitochondria isolated from mouse liver, kidney, heart, and skeletal muscle. Carboxyatractyloside titrations were also performed with the assay to estimate the flux control strength of the adenine nucleotide translocase (ANT) over OxPhos in human skeletal muscle mitochondria. ANT flux control coefficients were 0.91 ± 0.07, 0.83 ± 0.06, and 0.51 ± 0.07 at ADP concentrations of 6.25, 12.5, and 25 μM, respectively, an [ADP] range which spanned the K0.5ADP. The oxidative capacity of substrate combinations added to drive OxPhos was found to dramatically influence ADP kinetics in mitochondria from several tissues. In mouse skeletal muscle ten different substrate combinations elicited a 7-fold range of OxPhos Vmax, which correlated positively (R2 = 0.963) with K0.5ADP values ranging from 2.3 ± 0.2 μM to 11.9 ± 0.6 μM. We propose that substrate-enhanced capacity to generate the protonmotive force increases the OxPhos K0.5ADP because flux control at ANT increases, thus K0.5ADP rises toward the dissociation constant, KdADP, of ADP-ANT binding. The findings are discussed in the context of top-down metabolic control analysis.
Collapse
Affiliation(s)
- Wayne Willis
- Department of Medicine, Division of Endocrinology, University of Arizona, Tucson, AZ, United States; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona, Tucson, AZ, United States.
| | - Elizabeth Willis
- College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Sarah Kuzmiak-Glancy
- Department of Kinesiology, University of Maryland, College Park, MD, United States
| | - Katon Kras
- Department of Medicine, Division of Endocrinology, University of Arizona, Tucson, AZ, United States
| | - Jamie Hudgens
- College of Pharmacy, Midwestern University, Glendale, AZ, United States
| | - Neusha Barakati
- Department of Medicine, Division of Endocrinology, University of Arizona, Tucson, AZ, United States
| | - Jennifer Stern
- Department of Medicine, Division of Endocrinology, University of Arizona, Tucson, AZ, United States; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona, Tucson, AZ, United States
| | - Lawrence Mandarino
- Department of Medicine, Division of Endocrinology, University of Arizona, Tucson, AZ, United States; Center for Disparities in Diabetes, Obesity, and Metabolism, University of Arizona, Tucson, AZ, United States
| |
Collapse
|
4
|
Mitochondrial Functions, Energy Metabolism and Protein Glycosylation are Interconnected Processes Mediating Resistance to Bortezomib in Multiple Myeloma Cells. Biomolecules 2020; 10:biom10050696. [PMID: 32365811 PMCID: PMC7277183 DOI: 10.3390/biom10050696] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 03/31/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
The proteasome inhibitor bortezomib (BTZ) has emerged as an effective drug for the treatment of multiple myeloma even though many patients relapse from BTZ therapy. The present study investigated the metabolic pathways underlying the acquisition of bortezomib resistance in multiple myeloma. We used two different clones of multiple myeloma cell lines exhibiting different sensitivities to BTZ (U266 and U266-R) and compared them in terms of metabolic profile, mitochondrial fitness and redox balance homeostasis capacity. Our results showed that the BTZ-resistant clone (U266-R) presented increased glycosylated UDP-derivatives when compared to BTZ-sensitive cells (U266), thus also suggesting higher activities of the hexosamine biosynthetic pathway (HBP), regulating not only protein O- and N-glycosylation but also mitochondrial functions. Notably, U266-R displayed increased mitochondrial biogenesis and mitochondrial dynamics associated with stronger antioxidant defenses. Furthermore, U266-R maintained a significantly higher concentration of substrates for protein glycosylation when compared to U266, particularly for UDP-GlcNac, thus further suggesting the importance of glycosylation in the BTZ pharmacological response. Moreover, BTZ-treated U266-R showed significantly higher ATP/ADP ratios and levels of ECP and also exhibited increased mitochondrial fitness and antioxidant response. In conclusions, our findings suggest that the HBP may play a major role in mitochondrial fitness, driving BTZ resistance in multiple myeloma and thus representing a possible target for new drug development for BTZ-resistant patients.
Collapse
|
5
|
Willis WT, Miranda-Grandjean D, Hudgens J, Willis EA, Finlayson J, De Filippis EA, Zapata Bustos R, Langlais PR, Mielke C, Mandarino LJ. Dominant and sensitive control of oxidative flux by the ATP-ADP carrier in human skeletal muscle mitochondria: Effect of lysine acetylation. Arch Biochem Biophys 2018; 647:93-103. [PMID: 29653079 DOI: 10.1016/j.abb.2018.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/29/2018] [Accepted: 04/08/2018] [Indexed: 02/01/2023]
Abstract
The adenine nucleotide translocase (ANT) of the mitochondrial inner membrane exchanges ADP for ATP. Mitochondria were isolated from human vastus lateralis muscle (n = 9). Carboxyatractyloside titration of O2 consumption rate (Jo) at clamped [ADP] of 21 μM gave ANT abundance of 0.97 ± 0.14 nmol ANT/mg and a flux control coefficient of 82% ± 6%. Flux control fell to 1% ± 1% at saturating (2 mM) [ADP]. The KmADP for Jo was 32.4 ± 1.8 μM. In terms of the free (-3) ADP anion this KmADP was 12.0 ± 0.7 μM. A novel luciferase-based assay for ATP production gave KmADP of 13.1 ± 1.9 μM in the absence of ATP competition. The free anion KmADP in this case was 2.0 ± 0.3 μM. Targeted proteomic analyses showed significant acetylation of ANT Lysine23 and that ANT1 was the most abundant isoform. Acetylation of Lysine23 correlated positively with KmADP, r = 0.74, P = 0.022. The findings underscore the central role played by ANT in the control of oxidative phosphorylation, particularly at the energy phosphate levels associated with low ATP demand. As predicted by molecular dynamic modeling, ANT Lysine23 acetylation decreased the apparent affinity of ADP for ANT binding.
Collapse
Affiliation(s)
- W T Willis
- University of Arizona, College of Medicine, Department of Medicine, 1501 N. Campbell Avenue, P.O. Box 245099, Tucson, AZ 85724-5099, USA.
| | - D Miranda-Grandjean
- Mayo Clinic, Division of Endocrinology, East Shea Boulevard and 134th Street, Scottsdale, AZ 85259, USA.
| | - J Hudgens
- Mayo Clinic, Division of Endocrinology, East Shea Boulevard and 134th Street, Scottsdale, AZ 85259, USA.
| | - E A Willis
- Mayo Clinic, Division of Endocrinology, East Shea Boulevard and 134th Street, Scottsdale, AZ 85259, USA.
| | - J Finlayson
- University of Arizona, College of Medicine, Department of Medicine, 1501 N. Campbell Avenue, P.O. Box 245099, Tucson, AZ 85724-5099, USA.
| | - E A De Filippis
- Mayo Clinic, Division of Endocrinology, East Shea Boulevard and 134th Street, Scottsdale, AZ 85259, USA.
| | - R Zapata Bustos
- University of Arizona, College of Medicine, Department of Medicine, 1501 N. Campbell Avenue, P.O. Box 245099, Tucson, AZ 85724-5099, USA.
| | - P R Langlais
- University of Arizona, College of Medicine, Department of Medicine, 1501 N. Campbell Avenue, P.O. Box 245099, Tucson, AZ 85724-5099, USA.
| | - C Mielke
- Mayo Clinic, Division of Endocrinology, East Shea Boulevard and 134th Street, Scottsdale, AZ 85259, USA.
| | - L J Mandarino
- University of Arizona, College of Medicine, Department of Medicine, 1501 N. Campbell Avenue, P.O. Box 245099, Tucson, AZ 85724-5099, USA.
| |
Collapse
|
6
|
Fink BD, Bai F, Yu L, Sivitz WI. Regulation of ATP production: dependence on calcium concentration and respiratory state. Am J Physiol Cell Physiol 2017; 313:C146-C153. [PMID: 28515085 DOI: 10.1152/ajpcell.00086.2017] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 12/12/2022]
Abstract
Nanomolar free calcium enhances oxidative phosphorylation. However, the effects over a broad concentration range, at different respiratory states, or on specific energy substrates are less clear. We examined the action of varying [Ca2+] over respiratory states ranging 4 to 3 on skeletal muscle mitochondrial respiration, potential, ATP production, and H2O2 production using ADP recycling to clamp external [ADP]. Calcium at 450 nM enhanced respiration in mitochondria energized by the complex I substrates, glutamate/malate (but not succinate), at [ADP] of 4-256 µM, but more substantially at intermediate respiratory states and not at all at state 4. Using varied [Ca2+], we found that the stimulatory effects on respiration and ATP production were most prominent at nanomolar concentrations, but inhibitory at 10 µM or higher. ATP production decreased more than respiration at 10 µM calcium. However, potential continued to increase up to 10 µM; suggesting a calcium-induced inability to utilize potential for phosphorylation independent of opening of the mitochondrial permeability transition pore (MTP). This effect of 10 µM calcium was confirmed by direct determination of ATP production over a range of potential created by differing substrate concentrations. Consistent with past reports, nanomolar [Ca2+] had a stimulatory effect on utilization of potential for phosphorylation. Increasing [Ca2+] was positively and continuously associated with H2O2 production. In summary, the stimulatory effect of calcium on mitochondrial function is substrate dependent and most prominent over intermediate respiratory states. Calcium stimulates or inhibits utilization of potential for phosphorylation dependent on concentration with inhibition at higher concentration independent of MTP opening.
Collapse
Affiliation(s)
- Brian D Fink
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, Iowa
| | - Fan Bai
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, Iowa
| | - Liping Yu
- Department of Biochemistry, University of Iowa, Iowa City, Iowa; and.,NMR Core Facility, University of Iowa, Iowa City, Iowa
| | - William I Sivitz
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, Iowa;
| |
Collapse
|
7
|
Fink BD, Bai F, Yu L, Sivitz WI. Impaired utilization of membrane potential by complex II-energized mitochondria of obese, diabetic mice assessed using ADP recycling methodology. Am J Physiol Regul Integr Comp Physiol 2016; 311:R756-R763. [PMID: 27558314 DOI: 10.1152/ajpregu.00232.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/08/2016] [Accepted: 08/22/2016] [Indexed: 11/22/2022]
Abstract
Recently, we used an ADP recycling approach to examine mouse skeletal muscle (SkM) mitochondrial function over respiratory states intermittent between state 3 and 4. We showed that respiration energized at complex II by succinate, in the presence of rotenone to block complex I, progressively increased with incremental additions of ADP. However, in the absence of rotenone, respiration peaked at low [ADP] but then dropped markedly as [ADP] was further increased. Here, we tested the hypothesis that these respiratory dynamics would differ between mitochondria of mice fed high fat (HF) and treated with a low dose of streptozotocin to mimic Type 2 diabetes and mitochondria from controls. We found that respiration and ATP production on succinate alone for both control and diabetic mice increased to a maximum at low [ADP] but dropped markedly as [ADP] was incrementally increased. However, peak respiration by the diabetic mitochondria required a higher [ADP] (right shift in the curve of O2 flux vs. [ADP]). ATP production by diabetic mitochondria respiring on succinate alone was significantly less than controls, whereas membrane potential trended higher, indicating that utilization of potential for oxidative phosphorylation was impaired. The rightward shift in the curve of O2 flux versus [ADP] is likely a consequence of these changes in ATP production and potential. In summary, using an ADP recycling approach, we demonstrated that ATP production by SkM mitochondria of HF/streptozotocin diabetic mice energized by succinate is impaired due to decreased utilization of ΔΨ and that more ADP is required for peak O2 flux.
Collapse
Affiliation(s)
- Brian D Fink
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, Iowa
| | - Fan Bai
- Department of Biochemistry, University of Iowa; and
| | - Liping Yu
- Department of Biochemistry, University of Iowa; and.,NMR Core Facility, University of Iowa, Iowa City, Iowa
| | - William I Sivitz
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, Iowa;
| |
Collapse
|
8
|
Bai F, Fink BD, Yu L, Sivitz WI. Voltage-Dependent Regulation of Complex II Energized Mitochondrial Oxygen Flux. PLoS One 2016; 11:e0154982. [PMID: 27153112 PMCID: PMC4859540 DOI: 10.1371/journal.pone.0154982] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/23/2016] [Indexed: 01/04/2023] Open
Abstract
Oxygen consumption by isolated mitochondria is generally measured during state 4 respiration (no ATP production) or state 3 (maximal ATP production at high ADP availability). However, mitochondria in vivo do not function at either extreme. Here we used ADP recycling methodology to assess muscle mitochondrial function over intermediate clamped ADP concentrations. In so doing, we uncovered a previously unrecognized biphasic respiratory pattern wherein O2 flux on the complex II substrate, succinate, initially increased and peaked over low clamped ADP concentrations then decreased markedly at higher clamped concentrations. Mechanistic studies revealed no evidence that the observed changes in O2 flux were due to altered opening or function of the mitochondrial permeability transition pore or to changes in reactive oxygen. Based on metabolite and functional metabolic data, we propose a multifactorial mechanism that consists of coordinate changes that follow from reduced membrane potential (as the ADP concentration in increased). These changes include altered directional electron flow, altered NADH/NAD+ redox cycling, metabolite exit, and OAA inhibition of succinate dehydrogenase. In summary, we report a previously unrecognized pattern for complex II energized O2 flux. Moreover, our findings suggest that the ADP recycling approach might be more widely adapted for mitochondrial studies.
Collapse
Affiliation(s)
- Fan Bai
- Department of Biochemistry, University of Iowa, Iowa City, IA, 52242, United States of America
| | - Brian D. Fink
- Department of Internal Medicine / Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, IA, 52242, United States of America
| | - Liping Yu
- Department of Biochemistry, University of Iowa, Iowa City, IA, 52242, United States of America
- NMR Core Facility, University of Iowa, Iowa City, IA, 52242, United States of America
| | - William I. Sivitz
- Department of Internal Medicine / Endocrinology and Metabolism, University of Iowa and the Iowa City Veterans Affairs Medical Center, Iowa City, IA, 52242, United States of America
- * E-mail:
| |
Collapse
|
9
|
Glancy B, Willis WT, Chess DJ, Balaban RS. Effect of calcium on the oxidative phosphorylation cascade in skeletal muscle mitochondria. Biochemistry 2013; 52:2793-809. [PMID: 23547908 DOI: 10.1021/bi3015983] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Calcium is believed to regulate mitochondrial oxidative phosphorylation, thereby contributing to the maintenance of cellular energy homeostasis. Skeletal muscle, with an energy conversion dynamic range of up to 100-fold, is an extreme case for evaluating the cellular balance of ATP production and consumption. This study examined the role of Ca(2+) in the entire oxidative phosphorylation reaction network in isolated skeletal muscle mitochondria and attempted to extrapolate these results back to the muscle, in vivo. Kinetic analysis was conducted to evaluate the dose-response effect of Ca(2+) on the maximal velocity of oxidative phosphorylation (V(maxO)) and the ADP affinity. Force-flow analysis evaluated the interplay between energetic driving forces and flux to determine the conductance, or effective activity, of individual steps within oxidative phosphorylation. Measured driving forces [extramitochondrial phosphorylation potential (ΔG(ATP)), membrane potential, and redox states of NADH and cytochromes b(H), b(L), c(1), c, and a,a(3)] were compared with flux (oxygen consumption) at 37 °C; 840 nM Ca(2+) generated an ~2-fold increase in V(maxO) with no change in ADP affinity (~43 μM). Force-flow analysis revealed that Ca(2+) activation of V(maxO) was distributed throughout the oxidative phosphorylation reaction sequence. Specifically, Ca(2+) increased the conductance of Complex IV (2.3-fold), Complexes I and III (2.2-fold), ATP production/transport (2.4-fold), and fuel transport/dehydrogenases (1.7-fold). These data support the notion that Ca(2+) activates the entire muscle oxidative phosphorylation cascade, while extrapolation of these data to the exercising muscle predicts a significant role of Ca(2+) in maintaining cellular energy homeostasis.
Collapse
Affiliation(s)
- Brian Glancy
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | |
Collapse
|
10
|
Glancy B, Barstow T, Willis WT. Linear relation between time constant of oxygen uptake kinetics, total creatine, and mitochondrial content in vitro. Am J Physiol Cell Physiol 2007; 294:C79-87. [PMID: 17942641 DOI: 10.1152/ajpcell.00138.2007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Following the onset of moderate aerobic exercise, the rate of oxygen consumption (J(o)) rises monoexponentially toward the new steady state with a time constant (tau) in the vicinity of 30 s. The mechanisms underlying this delay have been studied over several decades. Meyer's electrical analog model proposed the concept that the tau is given by tau = R(m) x C, where R(m) is mitochondrial resistance to energy transfer, and C is metabolic capacitance, determined primarily by the cellular total creatine pool (TCr = phosphocreatine + creatine). The purpose of this study was to evaluate in vitro the J(o) kinetics of isolated rat skeletal muscle mitochondria at various levels of TCr and mitochondrial protein. Mitochondria were incubated in a medium containing 5.0 mM ATP, TCr pools of 0-1.5 mM, excess creatine kinase, and an ATP-splitting system of glucose + hexokinase (HK). Pyruvate and malate (1 mM each) were present as oxidative substrates. J(o) was measured across time after HK was added to elicit one of two levels of J(o) (40 and 60% of state 3). At TCr levels (in mM) of 0.1, 0.2, 0.3, 0.75, and 1.5, the corresponding tau values (s, means +/- SE) were 22.2 +/- 3.0, 36.3 +/- 2.2, 65.7 +/- 4.3, 168.1 +/- 22.2, and 287.3 +/- 25.9. Thus tau increased linearly with TCr (R(2) = 0.916). Furthermore, the experimentally observed tau varied linearly and inversely with the mitochondrial protein added. These in vitro results consistently conform to the predictions of Meyer's electrical analog model.
Collapse
Affiliation(s)
- Brian Glancy
- Department of Kinesiology, Arizona State University, Tempe, AZ 85287-0404, USA
| | | | | |
Collapse
|
11
|
Metelkin E, Goryanin I, Demin O. Mathematical modeling of mitochondrial adenine nucleotide translocase. Biophys J 2005; 90:423-32. [PMID: 16239329 PMCID: PMC1367049 DOI: 10.1529/biophysj.105.061986] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have developed a mathematical model of adenine nucleotide translocase (ANT) function on the basis of the structural and kinetic properties of the transporter. The model takes into account the effect of membrane potential, pH, and magnesium concentration on ATP and ADP exchange velocity. The parameters of the model have been estimated from experimental data. A satisfactory model should take into account the influence of the electric potential difference on both ternary complex formation and translocation processes. To describe the dependence of translocation constants on electric potential we have supposed that ANT molecules carry charged groups. These groups are shifted during the translocation. Using the model we have evaluated the translocator efficiency and predicted the behavior of ANT under physiological conditions.
Collapse
Affiliation(s)
- Eugeniy Metelkin
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov, Moscow State University, Moscow, Russia.
| | | | | |
Collapse
|
12
|
Abstract
Diabetes mellitus is the most common genetic disease in the Western world today. It is the phenotype for >150 genotypes. Each of these genotypes is characterized by impaired glucose tolerance and impaired control of intermediary metabolism. There are many strains of mice and rats that can be used to study diabetes in its various forms. One of these is the BHE/Cdb rat, which mimics the human phenotype with a mutation in the mitochondrial (mt) DNA. The result of such mutation is a loss in metabolic control with respect to the role of the mitochondria in this control. This review addresses those aspects of control that are exerted by mt oxidative phosphorylation (OXPHOS). Diet can have both genomic and nongenomic effects on OXPHOS. The type of dietary fat influences the fluidity of the mt membranes and hence, mt function. The dietary fat effect depends on the genetic background of the consumer. Diabetes-prone BHE/Cdb rats with base substitutions in the mt ATPase 6 gene are more likely to be influenced by the diet effect on mt membrane fluidity than are normal rats. Vitamin A also affects mt function through an effect on mt gene expression. BHE/Cdb rats have a greater need for vitamin A than normal rats and supplemental vitamin A appears to influence OXPHOS.
Collapse
Affiliation(s)
- C D Berdanier
- Department of Foods and Nutrition, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
13
|
Scaduto RC, Grotyohann LW. 2,3-butanedione monoxime unmasks Ca(2+)-induced NADH formation and inhibits electron transport in rat hearts. Am J Physiol Heart Circ Physiol 2000; 279:H1839-48. [PMID: 11009471 DOI: 10.1152/ajpheart.2000.279.4.h1839] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used 2,3-butanedione monoxime (BDM) to suppress work by the perfused rat heart and to investigate the effects of calcium on NADH production and tissue energetics. Hearts were perfused with buffer containing BDM and elevated perfusate calcium to maintain the rates of cardiac work and oxygen consumption at levels similar to those of control perfused hearts. BDM plus calcium hearts displayed higher levels of NADH surface fluorescence, indicating calcium activation of mitochondrial dehydrogenases. These hearts, however, displayed 20% lower phosphocreatine levels. BDM suppressed the rates of state 3 respiration of isolated mitochondria. Uncoupled respiration was suppressed to a lesser degree, and the state 4 respiration rates were not affected. Double-inhibitor experiments with liver mitochondria using BDM and carboxyatractyloside (CAT) were used to identify the site of inhibition. BDM at low levels (0-5 mM) suppressed respiration. In the presence of CAT at levels that inhibit respiration by 60%, low levels of BDM were without effect. Because these effects were not additive, BDM does not inhibit adenine nucleotide transport. This was supported by an assay of adenine nucleotide transport in liver mitochondria. BDM did not inhibit ATP hydrolysis by submitochondrial particles but strongly suppressed reversed electron transport from succinate to NAD(+). Oxidation of NADH by submitochondrial particles was inhibited by BDM but oxidation of succinate was not. We conclude that BDM inhibits electron transport at site 1.
Collapse
Affiliation(s)
- R C Scaduto
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Pennsylvania State University, Hershey, Pennsylvania 17033, USA.
| | | |
Collapse
|
14
|
Studies of Physiological Control of ATP Synthesis. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s1569-2558(08)60252-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
15
|
Inomoto T, Tanaka A, Mori S, Jin MB, Sato B, Yanabu N, Tokuka A, Kitai T, Ozawa K, Yamaoka Y. Changes in the distribution of the control of the mitochondrial oxidative phosphorylation in regenerating rabbit liver. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1188:311-7. [PMID: 7803448 DOI: 10.1016/0005-2728(94)90050-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Applying the metabolic control theory, inhibitor titration studies were carried out on Complex I, III, IV, ATP synthase, ATP/ADP carrier and P(i) carrier of mitochondrial oxidative phosphorylation in normal and regenerating rabbit liver in order to examine the acceleration mechanism of mitochondrial oxidative phosphorylation. In regenerating rabbit liver the rate of state 3 respiration, respiratory control ratio and phosphorylation rate in the presence of mM glutamate, 250 microM ADP and 3 mM inorganic phosphate increased significantly as compared with the control by 73%, 48% and 76%, respectively. The control of the rate of state 3 respiration in normal liver was exerted by Complexes I, IV and steps other than the aforementioned six steps, whose flux control coefficients were 0.317, 0.214 and 0.469, respectively. By contrast, in regenerating liver, the control was more evenly distributed among these steps in oxidative phosphorylation and the possibility is suggested that Complexes I, IV and steps other than the six steps are activated during regeneration. The activation of Complexes I and IV was attributed to their increased activity, since it was not accompanied by an increase in the amount of the enzymes.
Collapse
Affiliation(s)
- T Inomoto
- Second Department of Surgery, Faculty of Medicine, Kyoto University, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Scaduto RC. Calcium and 2-oxoglutarate-mediated control of aspartate formation by rat heart mitochondria. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 223:751-8. [PMID: 7914488 DOI: 10.1111/j.1432-1033.1994.tb19049.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Studies of the influence of calcium on the metabolism of cardiac mitochondria have indicated that calcium activates key enzymes involved in the citric acid cycle. Calcium-mediated activation of one of these enzymes, 2-oxoglutarate dehydrogenase, has been shown to cause a marked decrease in the steady-state concentration of 2-oxoglutarate in both heart and liver mitochondria. In liver, 2-oxoglutarate is a potent inhibitor of oxalacetate transamination to aspartate and activation of this enzyme by calcium-mobilizing hormones leads to a stimulation of aspartate formation and gluconeogenesis. Since mitochondrial aspartate formation is a key step in the malate/aspartate shuttle, we investigated the control of aspartate formation by cardiac mitochondria. In mitochondria incubated with glutamate and malate, activation of 2-oxoglutarate dehydrogenase by calcium led to an inhibition of aspartate formation. However, calcium caused a stimulation of aspartate production when incubations were supplemented with pyruvate as an additional substrate. Estimates of the mitochondrial redox potential (NADH/NAD+) indicated that both calcium and pyruvate increased the redox potential. The observed influence of calcium on aspartate formation was found to be due to a balance between is inhibitory effect, caused by an increased redox potential, and its stimulatory effect, caused by a decreased 2-oxoglutarate concentration. Under conditions in which the redox component was held constant, a kinetic analysis indicated that the apparent Ki for 2-oxoglutarate inhibition of aspartate formation is 0.2 mM. The data suggest that activation of cardiac 2-oxoglutarate dehydrogenase by calcium could lead to stimulation of the mitochondrial oxidation of cytosolic NADH via the malate/aspartate cycle.
Collapse
Affiliation(s)
- R C Scaduto
- Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033
| |
Collapse
|
17
|
Wisniewski E, Kunz W, Gellerich F. Phosphate affects the distribution of flux control among the enzymes of oxidative phosphorylation in rat skeletal muscle mitochondria. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)98356-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
18
|
Borutaité V, Mildaziene V, Katiliuté Z, Kholodenko B, Toleikis A. The function of ATP/ADP translocator in the regulation of mitochondrial respiration during development of heart ischemic injury. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1142:175-80. [PMID: 8457582 DOI: 10.1016/0005-2728(93)90099-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Inhibitor titration studies were carried out in order to quantify the amount of control exerted by ATP/ADP translocator on the rate of succinate, palmitoylcarnitine + malate and pyruvate + malate oxidation in ischemia-damaged heart mitochondria. It was shown that after 30 min of total ischemia in vitro the maximal value of the control coefficient of the translocator was as high as in the control: 0.5-0.72 (succinate), 0.8-0.87 (palmitoylcarnitine + malate), 0.83-0.95 (pyruvate+malate). However, the translocator-controlled range of respiratory rates of ischemic mitochondria was narrower than that of normal mitochondria. The control coefficient of the translocator close to State 3 and State 4 was equal to 0-0.15. After 45 min ischemia the maximal value of the translocator control coefficient decreased by 25-30% in comparison with normal mitochondria with all substrates investigated. This value was preserved within a wide range of mitochondrial respiratory rates including the maximal rate in State 3. It was found that the amount of ATP/ADP translocator in mitochondria decreased by 20% after only 45 min ischemia. Our data show that the ATP/ADP translocator is one of the most important steps in regulation of oxidative phosphorylation in isolated mitochondria during development of heart ischemic injury.
Collapse
Affiliation(s)
- V Borutaité
- Biomedical Research Institute of Kaunas Medical Academy, Kaunas, Lithuania
| | | | | | | | | |
Collapse
|
19
|
Abstract
We have seen that there is no simple answer to the question 'what controls respiration?' The answer varies with (a) the size of the system examined (mitochondria, cell or organ), (b) the conditions (rate of ATP use, level of hormonal stimulation), and (c) the particular organ examined. Of the various theories of control of respiration outlined in the introduction the ideas of Chance & Williams (1955, 1956) give the basic mechanism of how respiration is regulated. Increased ATP usage can cause increased respiration and ATP synthesis by mass action in all the main tissues. Superimposed on this basic mechanism is calcium control of matrix dehydrogenases (at least in heart and liver), and possibly also of the respiratory chain (at least in liver) and ATP synthase (at least in heart). In many tissues calcium also stimulates ATP usage directly; thus calcium may stimulate energy metabolism at (at least) four possible sites, the importance of each regulation varying with tissue. Regulation of multiple sites may occur (from a teleological point of view) because: (a) energy metabolism is branched and thus proportionate regulation of branches is required in order to maintain constant fluxes to branches (e.g. to proton leak or different ATP uses); and/or (b) control over fluxes is shared by a number of reactions, so that large increases in flux requires stimulation at multiple sites because each site has relatively little control. Control may be distributed throughout energy metabolism, possibly due to the necessity of minimizing cell protein levels (see Brown, 1991). The idea that energy metabolism is regulated by energy charge (as proposed by Atkinson, 1968, 1977) is misleading in mammals. Neither mitochondrial ATP synthesis nor cellular ATP usage is a unique function of energy charge as AMP is not a significant regulator (see for example Erecinska et al., 1977). The near-equilibrium hypothesis of Klingenberg (1961) and Erecinska & Wilson (1982) is partially correct in that oxidative phosphorylation is often close to equilibrium (apart from cytochrome oxidase) and as a consequence respiration and ATP synthesis are mainly regulated by (a) the phosphorylation potential, and (b) the NADH/NAD+ ratio. However, oxidative phosphorylation is not always close to equilibrium, at least in isolated mitochondria, and relative proximity to equilibrium does not prevent the respiratory chain, the proton leak, the ATP synthase and ANC having significant control over the fluxes. Thus in some conditions respiration rate correlates better with [ADP] than with phosphorylation potential, and may be relatively insensitive to mitochondrial NADH/NAD+ ratio.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
Affiliation(s)
- G C Brown
- Department of Biochemistry and Molecular Biology, University College London, U.K
| |
Collapse
|
20
|
Moreno-Sánchez R, Devars S, López-Gómez F, Uribe A, Corona N. Distribution of control of oxidative phosphorylation in mitochondria oxidizing NAD-linked substrates. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1060:284-92. [PMID: 1751513 DOI: 10.1016/s0005-2728(05)80318-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The flux control distribution of the net rate of state 3 respiration was determined in heart and kidney mitochondria incubated with low concentrations of pyruvate (0.5 mM) or 2-oxoglutarate (1 mM), and in conditions that led to activation of NAD-linked dehydrogenases, i.e., high substrate or Ca2+ concentrations. Control of flux was exerted by the ATP/ADP carrier (flux control coefficient, ci = 0.37) and Site 1 of the respiratory chain (ci = 0.28) when dehydrogenase activity was low. Control of the process shifted to the ATP synthase (ci = 0.32) and the Pi carrier (Ci = 0.27) when dehydrogenases were activated by high pyruvate and high Ca2+. The changes in the control exerted by the ATP/ADP carrier and the ATP synthase were not due to changes in the transmembrane potential, nor to a modification of intramitochondrial ATP/ADP ratios. Applying the summation theorem of the control analysis, it was found that at low Ca2+ and pyruvate concentrations the dehydrogenases shared the control of state 3 respiration with other steps. The NAD-linked dehydrogenases did not exert any significant control at high Ca2+ or high pyruvate concentrations.
Collapse
Affiliation(s)
- R Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, México, D.F
| | | | | | | | | |
Collapse
|
21
|
Davis EJ, Davis-van Thienen WI. An assessment of the role of proton leaks in the mechanistic stoichiometry of oxidative phosphorylation. Arch Biochem Biophys 1991; 289:184-6. [PMID: 1654845 DOI: 10.1016/0003-9861(91)90459-v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rat liver mitochondria were incubated in the presence of varying concentrations of ATP, followed by ADP to initiate phosphorylation. Analysis of phosphorylation to oxygen ratios (P/O) was carried out with varied initial phosphorylation potentials (or ATP/ADP ratios). Rates of phosphorylation and respiration and magnitude of membrane potential (delta psi) were measured. The results are discussed in the framework of P/total O and P/"extra" O ratios in determination of the mechanistic P/O ratio. It is concluded that the former underestimates, and the latter overestimates the mechanistic P/O ratio.
Collapse
Affiliation(s)
- E J Davis
- Indiana University School of Medicine, Department of Biochemistry and Molecular Biology, Indianapolis 46202-5122
| | | |
Collapse
|
22
|
Tummino PJ, Gafni A. A comparative study of succinate-supported respiration and ATP/ADP translocation in liver mitochondria from adult and old rats. Mech Ageing Dev 1991; 59:177-88. [PMID: 1890881 DOI: 10.1016/0047-6374(91)90083-c] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study was undertaken to compare the rates of succinate-supported hepatic mitochondrial respiration between 12 months (adult) and 29 months (old) male Fischer 344 rats. Experiments were also performed to determine the activity of adenine nucleotide translocase and the effect of its inhibition on mitochondrial respiration. Succinate-supported state 3 mitochondrial respiration was found to decline 20% between 12 and 29 months of age in rat liver, along with a similar 25% decrease in the respiratory control ratio with age. Adenine nucleotide translocase activity is shown to decrease 39% from adult to old rat liver mitochondria. This decrease does not, however, account for the decline in state 3 respiration, since translocase activity is approximately 50% greater than state 3 respiration in both adult and old rats. Therefore, adenine nucleotide translocase is not rate-limiting for state 3 mitochondrial respiration. Neither the rate of succinate permeation into the mitochondrial nor the rate of electron transport is rate-limiting for state 3 respiration, indicated by the greatly increased oxygen consumption with addition of the uncoupler carbonyl cyanide m-chlorophenyl hydrazone (m-CCCP). These processes, therefore, are not responsible for the observed decline in state 3 respiration. The implications and possible cause of the age-related decrease in the maximal rate of ATP-synthesis are discussed.
Collapse
Affiliation(s)
- P J Tummino
- Institute of Gerontology, University of Michigan, Ann Arbor 48109
| | | |
Collapse
|
23
|
Moreno-Sánchez R, Torres-Márquez ME. Control of oxidative phosphorylation in mitochondria, cells and tissues. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1991; 23:1163-74. [PMID: 1794441 DOI: 10.1016/0020-711x(91)90212-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- R Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, México D.F
| | | |
Collapse
|
24
|
Moreno-Sánchez R, Hogue BA, Hansford RG. Influence of NAD-linked dehydrogenase activity on flux through oxidative phosphorylation. Biochem J 1990; 268:421-8. [PMID: 2363681 PMCID: PMC1131449 DOI: 10.1042/bj2680421] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
1. We have examined systematically the relationship between the percentage reduction of cardiac mitochondrial NAD and the flux through oxidative phosphorylation, as measured by O2 uptake. Reduction of NAD was varied by varying the concentration of palmitoyl-L-carnitine, pyruvate, 2-oxoglutarate or glutamate in the presence of malate as the oxidizable substrate. 2. In the presence of ADP (State 3 respiration) there was a substantially linear positive relationship between O2 uptake and the percentage reduction of NAD. Coupled respiration in the absence of ADP also showed an increase with increasing NADH, with the exact shape of the relationship being variable. 3. When pyruvate and 2-oxoglutarate dehydrogenase activity were increased by increasing medium Ca2+ concentration within the range 5 nM to 1.23 microM, at non-saturating substrate concentrations, there was again a positive relationship between O2 uptake and the reduction of NAD; however, rates of O2 uptake tended to be higher at given values of NAD reduction when the incubation medium contained Ca2+. This is taken to indicate an activation by Ca2+ of the enzymes of phosphorylation or of the respiratory chain, in addition to the dehydrogenase activation. 4. When carboxyatractyloside plus ADP were used to generate 50% State 3 rates of O2 uptake with pyruvate or 2-oxoglutarate, sensitivity to Ca2+ was retained. However, when oligomycin plus 1 mM-ADP and 1 mM-ATP were used to generate 50% State 3, no such dependence was seen. 5. The results are interpreted to indicate a substantial role for substrate dehydrogenation in the overall regulation of oxidative phosphorylation when substrates are available at near-physiological concentrations.
Collapse
Affiliation(s)
- R Moreno-Sánchez
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | | | | |
Collapse
|
25
|
Abstract
By experiment and theory, formulae are derived to calculate the response of mitochondrial power supply, in flux and potential, to an ATP consuming enzyme load, incorporating effects of varying amounts of (i) enzyme, (ii) total circulating adenylate, and (iii) inhibition of the ATP/ADP translocase. The formulae, which apply between about 20% and 80% of maximum respiration, are the same as for the current and voltage of an electrical circuit in which a battery with potential, linear in the logarithm of the total adenylate, charges another battery whose opposing potential is also linear in the same logarithm, through three resistances. These resistances produce loss of potential due to dis-equilibrium of (i) intramitochondrial oxidative phosphorylation, (ii) the ATP/ADP translocase, and (iii) the ATP-consuming enzyme load. The model is represented geometrically by the following configuration: when potential is plotted against flux, the points lie on two pencils of lines each concurrent at zero respiration, the two pencils describing the respective characteristics of the mitochondrion and enzyme. Control coefficients and elasticities are calculated from the formulae.
Collapse
Affiliation(s)
- A T James
- Department of Statistics, University of Adelaide, Australia
| | | | | |
Collapse
|
26
|
Borutaite V, Mildaziene V, Ivanoviene L, Kholodenko B, Toleikis A, Praskevicius A. The role of long-chain acyl-CoA in the damage of oxidative phosphorylation in heart mitochondria. FEBS Lett 1989; 243:264-6. [PMID: 2917650 DOI: 10.1016/0014-5793(89)80141-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The aim of this investigation was to study the effect of intramitochondrial acyl-CoA on the respiration of rabbit heart mitochondria over the whole range of stationary respiratory rates between States 4 and 3. The creatine phosphokinase system was used for stabilization of extramitochondrial adenine nucleotide concentration. It was shown that acyl-CoA depressed respiration more effectively in the intermediate range of respiration between States 4 and 3. The effect of acyl-CoA was negligible near State 4 and in State 3. These data are in line with our previous results concerning the dependence of the adenine nucleotide translocator control coefficient on the rate of mitochondrial respiration. Thus, our data suggest that long-chain acyl-CoA may regulate oxidative phosphorylation in heart mitochondria in vivo.
Collapse
Affiliation(s)
- V Borutaite
- Central Research Laboratory, Kaunas Medical Institute, USSR
| | | | | | | | | | | |
Collapse
|
27
|
Kholodenko BN. How do external parameters control fluxes and concentrations of metabolites? An additional relationship in the theory of metabolic control. FEBS Lett 1988; 232:383-6. [PMID: 3378629 DOI: 10.1016/0014-5793(88)80775-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The flux through a metabolic pathway can be controlled by external signals from the environment. These signals are formally described as changes in external parameters, such as concentrations of external metabolites (substrates or effectors) or physical parameters, e.g. temperature, pH, ionic strength. It was proved that the response coefficient of the flux (or of the concentration) to a change in an external parameter is the weighted average of external elasticities of pathway enzymes towards this parameter; weight factors are the control coefficients of corresponding enzymes. As compared with the previously known relationships these ones are applicable to the more common case of parameters acting on more than one enzyme. Along with other applications, the use of the obtained relationships for control analysis of moiety-conserved cycles is considered.
Collapse
Affiliation(s)
- B N Kholodenko
- Research Institute for Technology and Safety of Drugs, Moscow, USSR
| |
Collapse
|
28
|
Affiliation(s)
- F L Hoch
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109
| |
Collapse
|
29
|
|
30
|
Brand MD, Murphy MP. Control of electron flux through the respiratory chain in mitochondria and cells. Biol Rev Camb Philos Soc 1987; 62:141-93. [PMID: 3300795 DOI: 10.1111/j.1469-185x.1987.tb01265.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
31
|
Abstract
1. The electron flux through cytochrome oxidase is a linear function of the net thermodynamic force across the complex over a limited range of conditions. 2. Over a wide range of conditions the electron flux is a complicated function of the percentage reduction of the cytochrome c pool and of delta psi (at low values of delta pH). 3. We have estimated the elasticities of electron flux through cytochrome oxidase to delta Eh of the redox reaction catalysed by cytochrome oxidase (or to cyt c2+/cyt c3+) and to delta psi. The elasticities varied depending on the values of delta psi and of the percentage reduction of the cytochrome c pool. 4. At intermediate rates (which may correspond to those in vivo) the electron flux through cytochrome oxidase is controlled to about the same extent by delta psi and by delta Eh.
Collapse
|