Inhibition of mitochondrial energy-linked functions by arsenate. Evidence for a nonhydrolytic mode of inhibitor action

Mitchell, Robert A.; Chang, B. C.; Huang, Cheng-Hsiung; DeMaster, Eugene G.

doi:10.1021/bi00787a013

Cited by 67 publications

(20 citation statements)

References 23 publications

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“…They proposed a slower rate of X-As hydrolysis compared to ADP-As hydrolysis as responsible, thus supporting their concept of a dual pathway of As uncoupling. In contrast, Mitchell et al (17) favors a nonhydrolytic mode of action of As and would explain the observations on kinetic grounds rather than as alternative energy-transfer pathways.…”

mentioning

confidence: 83%

Functioning of the Adenine Nucleotide Transporter in the Arsenate Uncoupling of Corn Mitochondria

Bertagnolli¹,

Hanson²

1973

Plant Physiol.

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Arsenate uncouples mitochondrial respiration in a process stimulated by ADP, inhibited by oligomycin, and competitively inhibited by inorganic phosphate. If mersalyl is added to corn mitochondria to block further transport of accumulated arsenate, the uncoupled respiration continues unabated due to recycling of matrix arsenate. Addition of ADP now inhibits rather than promotes respiration and the mitochondria shrink. It is established by arsenate analyses that arsenate is removed from the matrix. Oligomycin or atractyloside block the removal by inhibiting ADP-arsenate formation or transport, respectively. It is deduced that ADP-arsenate is stable in the membrane and is transported outward for hydrolysis in the external aqueous phase. Hence, ADP-arsenate formed in oxidative phosphorylation is not directly released to the matrix, and a mechanism must exist for its direct transfer to the transporter.The findings that arsenate uncoupling of mitochondrial respiration is oligomycin-sensitive (4,7,8,14,15), [6][7][8][9]15,21), and competitively inhibited by [5][6][7][8]21) has led to the opinion that instability of the ADP-As' bond formed in oxidative phosphorylation is responsible (7). It appears implicit in this view that the Fr7ATPase forms the arsenylated analog of ATP which is hydrolyzed either in the membrane or on release to the matrix, recycling As and ADP as acceptor. However, Ernster et al. (7) We report here on further studies of this phenomenon. The initial supposition is supported. The ADP-stimulation of arsenate uncoupling involves the AdN transporter, and it appears that oxidative phosphorylation-or arsenylation in this caseis accomplished without direct flux of adenine nucleotides in and out of the matrix. MATERIALS AND METHODSMitochondria. Corn mitochondria (Zea mays L. WF9(Tms)-xM14) were isolated, and recordings of oxygen consumption and percentage transmission were as previously described (10). Final suspension of the mitochondria (10-15 mg protein/ml) was in the same medium as used for the basic reaction mixture: 200 mm sucrose, 10 mm TES buffer, 1 mm MgSO, and 1 mg/ml bovine serum albumin, adjusted to pH 7.6 with KOH. Including a correction for the bovine serum albumin of the basic reaction mixture, protein concentrations were determined by the method of Lowry et al. (16). All preparations of mitochondria were checked for tight coupling by determining respiratory control and ADP/O ratios. Arsenate Transport. Radioactive 7"As (Amersham/Searle as arsenic acid in 0.04 M HCl) was mixed with potassium arsenate stock as carrier. For each experiment, a 0.1-ml aliquot of mitochondrial suspension was added to 0.9 ml of basic reaction mixture (28-29 C) with aeration by stirring. After additions (Table II), 100-1l aliquots (about 0.15 mg of protein) were withdrawn, and the mitochondria were collected on 0.45-,um pore size Millipore filters with suction being applied for 15 sec. The filters were dried, toluene based scintillation fluid (toluene-PPO-POPOP) was added, and the vials were counted.Atracty...

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mentioning

confidence: 83%

Functioning of the Adenine Nucleotide Transporter in the Arsenate Uncoupling of Corn Mitochondria

Bertagnolli¹,

Hanson²

1973

Plant Physiol.

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“…Most exposure is through consumption of food and water. Although the mechanism of chronic arsenic toxicity is not known, studies of populations in Taiwan (156), Chile (157,158), and Mexico (159) (163), arsenite interacts with thiols and affects many functional proteins (164). As reviewed by Thompson (165), inorganic arsenic in the body is methylated by methyltransferase using S-adenosylmethionine as the methyl donor.…”

Section: Nutrition and Its Effects On Arsenic Toxicitymentioning

confidence: 99%

“…Populations exhibiting arsenic toxicity have mainly been of low economic status and suffering from some form of malnutrition. Nutritional studies in Chile revealed food energy and total protein intakes below recommended daily allowances (167 (163,173). That phosphate and arsenate can share the same transport mechanism is indicated by the decrease in intestinal absorption of arsenic with phosphate infusion in the rat (174).…”

Section: Nutrition and Its Effects On Arsenic Toxicitymentioning

confidence: 99%

Effects of Micronutrients on Metal Toxicity

Peraza¹,

Ayala-Fierro²,

Barber³

et al. 1998

Environmental Health Perspectives

109

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There is growing evidence that micronutrient intake has a significant effect on the toxicity and carcinogenesis caused by various chemicals. This paper examines the effect of micronutrient status on the toxicity of four nonessential metals: cadmium, lead, mercury, and arsenic. Unfortunately, few studies have directly examined the effect of dietary deficiency or supplementation on metal toxicity. More commonly, the effect of dietary alteration must be deduced from the results of mechanistic studies. We have chosen to separate the effect of micronutrients on toxic metals into three classes: interaction between essential micronutrients and toxic metals during uptake, binding, and excretion; influence of micronutrients on the metabolism of toxic metals; and effect of micronutrients on secondary toxic effects of metals. Based on data from mechanistic studies, the ability of micronutrients to modulate the toxicity of metals is indisputable. Micronutrients interact with toxic metals at several points in the body: absorption and excretion of toxic metals; transport of metals in the body; binding to target proteins; metabolism and sequestration of toxic metals; and finally, in secondary mechanisms of toxicity such as oxidative stress. Therefore, people eating a diet deficient in micronutrients will be predisposed to toxicity from nonessential metals.Environ Health Perspect 106(Suppl 1): 203-216 (1998). http://ehpnetl.niehs.nih.gov/docs/1998/Suppl-1/203-216peraza/abstract.html

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“…Cells exposed to 2-deoxyglucose are depleted of ATP (43). Sutherland et al (44) demonstrated that sodium metaarsenite, which inhibits oxidative phosphorylation and therefore results in intracellular ATP depletion, decreases hormoneactivated PEPCK promoter activity through a stress-activated pathway (45). Thus it is possible that 2-deoxyglucose represses the PEPCK gene by a mechanism unrelated to its role as a glucose analog.…”

Section: ␤-Actinmentioning

confidence: 99%

The Repression of Hormone-activated PEPCK Gene Expression by Glucose Is Insulin-independent but Requires Glucose Metabolism

Scott¹,

O’Doherty²,

Stafford³

et al. 1998

Journal of Biological Chemistry

102

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Phosphoenolpyruvate carboxykinase (PEPCK) is a rate-controlling enzyme in hepatic gluconeogenesis, and it therefore plays a central role in glucose homeostasis. The rate of transcription of the PEPCK gene is increased by glucagon (via cAMP) and glucocorticoids and is inhibited by insulin. Under certain circumstances glucose also decreases PEPCK gene expression, but the mechanism of this effect is poorly understood. The glucose-mediated stimulation of a number of glycolytic and lipogenic genes requires the expression of glucokinase (GK) and increased glucose metabolism. HL1C rat hepatoma cells are a stably transfected line of H4IIE rat hepatoma cells that express a PEPCK promoter-chloramphenicol acetyltransferase fusion gene that is regulated in the same manner as the endogenous PEPCK gene. These cells do not express GK and do not normally exhibit a response of either the endogenous PEPCK gene, or of the trans-gene, to glucose. A recombinant adenovirus that directs the expression of glucokinase (AdCMV-GK) was used to increase glucose metabolism in HL1C cells to test whether increased glucose flux is also required for the repression of PEPCK gene expression. In AdCMV-GK-treated cells glucose strongly inhibits hormone-activated transcription of the endogenous PEPCK gene and of the expressed fusion gene. The glucose effect on PEPCK gene promoter activity is blocked by 5 mM mannoheptulose, a specific inhibitor of GK activity. The glucose analog, 2-deoxyglucose mimics the glucose response, but this effect does not require GK expression. 3-O-methylglucose is ineffective. Glucose exerts its effect on the PEPCK gene within 4 h, at physiologic concentrations, and with an EC 50 of 6.5 mM, which approximates the K m of glucokinase. The effects of glucose and insulin on PEPCK gene expression are additive, but only at suboptimal concentrations of both agents. The results of these studies demonstrate that, by inhibiting PEPCK gene transcription, glucose participates in a feedback control loop that governs its production from gluconeogenesis.

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Inhibition of mitochondrial energy-linked functions by arsenate. Evidence for a nonhydrolytic mode of inhibitor action

Cited by 67 publications

References 23 publications

Functioning of the Adenine Nucleotide Transporter in the Arsenate Uncoupling of Corn Mitochondria

Functioning of the Adenine Nucleotide Transporter in the Arsenate Uncoupling of Corn Mitochondria

Effects of Micronutrients on Metal Toxicity

The Repression of Hormone-activated PEPCK Gene Expression by Glucose Is Insulin-independent but Requires Glucose Metabolism

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