Komplexbildner als Cofaktoren isolierter Zellgranula
TL;DR: Ethylenediaminetetra-aceticacid and other chelating agents of the same type inhibit the swelling of liver mitochondria and enhance their oxygen consumption and is probably due to complex formation of the Calcium ions.
Abstract: Ethylenediaminetetra-aceticacid and other chelating agents of the same type inhibit the swelling of liver mitochondria and enhance their oxygen consumption. This is probably due to complex formation of the Calcium ions.
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TL;DR: Experiments suggest that the factor competes successfully with actomyosin for the available Ca through its mechanism of Ca accumulation, and that it has no other direct influence on the biological activity of actomyOSin.
Abstract: The vesicles of fragmented sarcoplasmic reticulum, i.e. the physiological relaxing factor, remove most of the exchangeable Ca bound to actomyosin and myofibrils. The extent to which they remove Ca and the extent to which they inhibit myofibrillar activity are closely correlated. Previous work has shown that those in vitro reactions of actomyosin with ATP which are equivalent to its contraction, i.e. superprecipitation and a high ATPase activity, require the formation of a Ca-actomyosin complex, and that actomyosin after the removal of most of its bound Ca is inhibited by physiological concentrations of ATP. The evidence now suggests that the factor achieves its relaxing effect through the dissociation of the Ca-actomyosin complex and that it has no other direct influence on the biological activity of actomyosin. Experiments, showing that under similar conditions the vesicles of the factor are capable of reducing the concentration of ionized Ca in the surrounding medium to about 0.02 µM and less, suggest that the factor competes successfully with actomyosin for the available Ca through its mechanism of Ca accumulation.
231 citations
TL;DR: It is shown that the dependence of absorbance on mitochondrial concentration can be linearized, resulting in an intrinsic light scattering parameter which is independent of the concentration and source of mitochondria, and the absorbance osmotic curve is segmentally linear.
231 citations
01 Jan 1966
TL;DR: The energized calcium transport is described and the relaxing factors are discussed and the behavior of actomyosin in vitro and its correlation to in vivo contraction and relaxation of actonomyosin is discussed.
Abstract: Publisher Summary This chapter describes the energized calcium transport and discusses the relaxing factors. Analysis of the factors that might determine whether a muscle is relaxed or contracted and that regulate the transition from one state to the other is based on in vitro experiments. The chapter focuses on evaluation of the different conditions that cause relaxation. It discusses the behavior of actomyosin in vitro and its correlation to in vivo contraction and relaxation of actomyosin. In vitro contraction manifests by the development of tension in glycerol-extracted fiber bundles and shortening of fiber bundles or isolated myofibrils. When the calcium (Ca) level is lowered, myofibrils in vitro lose their bound Ca and adenosine triphosphate (ATP) permits relaxation to occur. The cytoplasmic Ca level of resting muscle, in vivo, is low. Living muscle has the means to remove Ca from the cytoplasm because it contains a specialized reticulum structure with a rapid transport system for Ca in addition to the Ca pumps of the mitochondria and the cell membrane
206 citations
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TL;DR: It is put forward that the levels of glutathione and ascorbic acid found in dietetic liver necrosis could be the result of changes occurring in a dead or dying liver left in the living body, and were not specific consequences of the dietetic lesion.
Abstract: 4. As a result of the findings, the suggestion is put forward that the levels of glutathione and ascorbic acid found in dietetic liver necrosis could be the result of changes occurring in a dead or dying liver left in the living body, and were not specific consequences of the dietetic lesion. Our thanks are due to Sir Harold Himsworth for his valuable advice and encouragement in this work. We are indebted to Miss S. Botha for her technical assistance. One of us (O. L.) was in receipt of a Research Grant from the Medical Research Council.
221 citations
163 citations
TL;DR: It was established that mitochondria are the morphologic units of the cyclophorase system and a close correlation was also observed between the state and number of mitochondria and the extent of cyclophOrase activity.
92 citations
TL;DR: In this paper, it is shown that le magnesium forme avec l'ATP un ion complexe, qui constituerait le veritable substrat de la reaction.
82 citations
TL;DR: The ability of soluble salts of ATP to solubilize numerous inorganic and organic compounds in neutral or slightly alkaline medium and to keep these compounds in solution is demonstrated.
34 citations