scholarly journals Reversible inhibition of adenine nucleotide translocation by long chain acyl-CoA esters in bovine heart mitochondria and inverted submitochondrial particles. Comparison with atractylate and bongkrekic acid.

1977 ◽  
Vol 252 (19) ◽  
pp. 6711-6714 ◽  
Author(s):  
B H Chua ◽  
E Shrago
1975 ◽  
Vol 148 (3) ◽  
pp. 533-537 ◽  
Author(s):  
R B Beechey ◽  
S A Hubbard ◽  
P E Linnett ◽  
A D Mitchell ◽  
E A Munn

An almost pure form of the bovine heart mitochondrial adenosine triphosphatase (ATPase) is released from the membrane by shaking submitochondrial particles with chloroform. Analyses on polyacrylamide gels and by electron microscopy, and also sensitivity to inhibitors, show that the chloroform-released enzyme is similar to other ATPase preparations from bovine heart mitochondria.


1984 ◽  
Vol 220 (2) ◽  
pp. 371-376 ◽  
Author(s):  
S Soboll ◽  
H J Seitz ◽  
H Sies ◽  
B Ziegler ◽  
R Scholz

The effect of long-chain acyl-CoA on subcellular adenine nucleotide systems was studied in the intact liver cell. Long-chain acyl-CoA content was varied by varying the nutritional state (fed and starved states) or by addition of oleate. Starvation led to an increase in the mitochondrial and a decrease in the cytosolic ATP/ADP ratio in liver both in vivo and in the isolated perfused organ as compared with the fed state. The changes were reversed on re-feeding glucose in liver in vivo or on infusion of substrates (glucose, glycerol) in the perfused liver, respectively. Similar changes in mitochondrial and cytosolic ATP/ADP ratios occurred on addition of oleate, but, importantly, not with a short-chain fatty acid such as octanoate. It is concluded that long-chain acyl-CoA exerts an inhibitory effect on mitochondrial adenine nucleotide translocation in the intact cell, as was previously postulated in the literature from data obtained with isolated mitochondria. The physiological relevance with respect to pyruvate metabolism, i.e. regulation of pyruvate carboxylase and pyruvate dehydrogenase by the mitochondrial ATP/ADP ratio, is discussed.


1985 ◽  
Vol 249 (3) ◽  
pp. H492-H497 ◽  
Author(s):  
K. Ichihara ◽  
J. R. Neely

The relationship between tissue levels of fatty acid metabolites in ischemic and reperfused hearts and recovery of mechanical function of these hearts on reperfusion was studied. Isolated rat hearts were exposed to global ischemia for periods up to 60 min under various conditions of coronary flow, O2 supply, and fatty acid concentrations and were then reperfused for either 15 or 30 min under aerobic conditions both with and without fatty acids present. Tissue levels of ATP, creatine phosphate, long-chain acyl CoA, and long-chain acyl carnitine were determined at the end of the ischemic and reperfusion periods. In some experiments K+ arrest during ischemia was used to prevent adenine nucleotide depletion both in the absence and presence of high fatty acids. Although the ability of these hearts to recover their preischemic mechanical function varied from 8 to 90% and tissue levels of acyl CoA and acyl carnitine during ischemia varied from 3- to 10-fold depending on the condition, no correlation was found between the recovery of function during reperfusion and either the presence of fatty acid or high levels of tissue long-chain acyl CoA and carnitine esters during ischemia.


1978 ◽  
Vol 77 (2) ◽  
pp. 417-426 ◽  
Author(s):  
CD Stoner ◽  
HD Sirak

Mg(2+) at an optimal concentration of 2mM (ph 6.5) induces large increases (up to 30 percent) in the optical density of bovine heart mitochondria incubated under conditions of low ionic strength (< approx. 0.01). The increases are associated with aggregation (sticking together) of the inner membranes and are little affected by changes in the energy status of the mitochondria. Virtually all of a number of other polyvalent cations tested and Ag(+) induce increases in mitochondrial optical density similar to those induced by Mg(2+), their approximate order of concentration effectiveness in respect to Mg(2+) being: La(3+) > Pb(2+) = Cu(2+) > Cd(2+) > Zn(2+) > Ag(+) > Mn(2+) > Ca(2+) > Mg(2+). With the exception of Mg(2+), all of these cations appear to induce swelling of the mitochondria concomitant with inner membrane aggregation. The inhibitors of the adenine nucleotide transport reaction carboxyatratyloside and bongkrekic acid are capable of preventing and reversing Mg(2+)-induced aggregation at the same low concentration required for complete inhibition of phosphorylating respiration, suggesting that they inhibit the aggregation by binding to the adenine nucleotide carrier. The findings are interpreted to indicate (a) that the inner mitochondrial membrane is normally prevented from aggregating by virtue of its net negative outer surface change, (b) that the cations induce the membrane to aggregate by binding at its outer surface, decreasing the net negative charge, and (c) that carboxyatractyloside and bongkrekic acid inhibit the aggregation by binding to the outer surface of the membrane, increasing the net negative charge.


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