Introduction

Green, Laura; Albert, D. K.

doi:10.1520/stp35517s

Cited by 3 publications

(4 citation statements)

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“…Although the calcium pump seems to be able to function without oxygen, the various substances studied here may well exert their effects preferentially upon phosphorylations associated in mitochondria with specific sites of the oxidative chain. We refer to current discussions about the several partial reactions associated with each of these oxidation sites (37,38,(49)(50)(51)(52)(53), and propose that in the sarcotubular system, too, ATP stands in relation to high energy intermediates A C or C -P (54, 55) the utilization of which is directly connected with the calcium accumulation or other transport phenomena (47,51,56). Since these partial reactions may differ quantitatively in the several sites, a wide variety of effects exerted by various modifiers becomes possible.…”

Section: I94mentioning

confidence: 99%

The Accumulation of Calcium Ions by Sarcotubular Vesicles

Carsten

Mommaerts

1964

The Journal of General Physiology

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The accumulation of Ca + + by microsomal (sarcotubular) preparations of rabbit skeletal muscle in the presence of oxalate, and the concurrent splitting of nucleoside triphosphate, displayed moderate nucleotide specificity in the sequence ATP > GTP, CTP, ITP > UTP > (ADP) > ATetraP for the former, ATP > (ADP) > ITP > GTP > CTP > UTP > ATetraP for the latter process. The "calcium pump" was weakly inhibited by caffeine, and was inhibited together with the ATPase by pyridoxalphosphate. Carnosine had no effect as such nor in the presence of pyridoxalphosphate except at high concentration; thiourea and p-chloromercuribenzoate were inhibiting while iodoacetate was inactive. Ca + accumulation and ATPase were inhibited by atabrine (not tested on ATPase), dinitrophenol, and amytal. High concentrations of oligomycin and rutamycin inhibited Ca++ uptake while slightly stimulating ATPase. Antimycin A stimulated the Ca++ uptake. These results are discussed in the light of their possible relation to partial reactions in oxidative phosphorylation. The Ca++ uptake and relaxing factor activities did not behave identically throughout. This is in part ascribed to changes in reactivity of actomyosin in the relaxation test, in part to the participation of relaxing substances other than the calcium pump.

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Section: I94mentioning

confidence: 99%

The Accumulation of Calcium Ions by Sarcotubular Vesicles

Carsten

Mommaerts

1964

The Journal of General Physiology

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“…However, the fact that DPNH is not oxidized directly by nuclear preparations without the addition of electron acceptors demonstrates that the quinone is not oxidized by atmospheric oxygen. In mitochondria the oxidation of reduced ubiquinone can take place via the cytochrome system (Green, 1959). The results obtained in this paper suggest that cytochrome oxidase is present in the nucleus and hence a similar mechanism of oxidation may exist.…”

Section: Discussionmentioning

confidence: 50%

The metabolism of isolated rat-liver nuclei

1961

Biochemical Journal

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“…4, 10) to a parallel orientation (Figs. 5,6). Further evidence of the morphological inconstancy of isolated mitochondria may be seen in Fig.…”

Section: Discussionmentioning

confidence: 70%

“…Prior to the reports by Linnane and Ziegler (5), Green (6), and Green et al (25,26), it was generally stated that isolated mitochondria are capable of catalyzing a slow oxidation of extramitochondrial D P N H (27)(28)(29)4). The rate is greatly stimulated by hypotonic treatment of the mitochondria (27) or by cytochrome c (28,29).…”

Section: Figurementioning

confidence: 99%

Morphology of Isolated Rabbit Heart Muscle Mitochondria and the Oxidation of Extramitochondrial Reduced Diphosphopyridine Nucleotide

Deshpande

Hickman

Korff

1961

The Journal of Cell Biology

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The morphology of rabbit heart muscle mitochondria isolated in several media has been compared by electron microscopy. The internal structure of isolated mitochondria differs from that of in situ mitochondria, with the Wpe and degree of alteration depending on the isolation medium. Examination of the isolated mitochondria after incubation revealed that additional morphological changes occurred during incubation, but these changes were less pronounced when the incubation was conducted in a complete medium containing substrate. The isolated mitochondria have been shown to be capable of catalyzing a slow aerobic oxidation of extramitochondrial reduced diphosphopyridine nucleotide. The rate of DPNH oxidation observed is sufficient to account for the ability of the mitochondria to oxidize lactate in the presence of catalytic amounts of DPNH. The suspensions used were essentially free of mitochondrial fragments, which arc known to oxidize DPNH. Possible relationships of these findings to metabolism in situ are discussed. The results indicate the desirability of correlating biochemical activities with the morphology of isolated mitochondria.Previous reports from this laboratory described the complete oxidation of L(+) lactate by rabbit heart muscle mitochondria in a medium supplemented with lactic dehydrogenasO and DPN + (2), and the conversion of fructose diphosphate to 3-phosphoglyceric acid under aerobic conditions in the presence of mitochondria, DPN +, and the appropriate glycolytic enzymes (3).x The following abbreviations are used:

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Introduction

Cited by 3 publications

References 0 publications

The Accumulation of Calcium Ions by Sarcotubular Vesicles

The Accumulation of Calcium Ions by Sarcotubular Vesicles

The metabolism of isolated rat-liver nuclei

Morphology of Isolated Rabbit Heart Muscle Mitochondria and the Oxidation of Extramitochondrial Reduced Diphosphopyridine Nucleotide

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