. Biological structure and function; proceedings. Biochemistry; Cytology. [02]=0 - Fig. I. Inhibition of succinate oxidation in rat liver mitochondria incubated with arsenate and dicoumarol [6]. Concentrations of the reagents in a final volume of 1-5 ml. were as follows: 0-05 M KCl, 0-033 ^ tris buffer pH 7-5, o-oo8 M MgClo, 0-05 M sucrose, 0-013 m succinate (Succ), 0-002 m arsenate (Arsen.), o-00006 M dicoumarol (Die.)- Mitochondria from 400 mg. rat liver wet weight (about 8 mg. protein). The substances were added at the points indicated. "1-3 Medium" stands for KCl, tris, MgCl and
. Biological structure and function; proceedings. Biochemistry; Cytology. [02]=0 - Fig. I. Inhibition of succinate oxidation in rat liver mitochondria incubated with arsenate and dicoumarol [6]. Concentrations of the reagents in a final volume of 1-5 ml. were as follows: 0-05 M KCl, 0-033 ^ tris buffer pH 7-5, o-oo8 M MgClo, 0-05 M sucrose, 0-013 m succinate (Succ), 0-002 m arsenate (Arsen.), o-00006 M dicoumarol (Die.)- Mitochondria from 400 mg. rat liver wet weight (about 8 mg. protein). The substances were added at the points indicated. "1-3 Medium" stands for KCl, tris, MgCl and sucrose added in a volume of i -3 ml. Oxidation rate of succinate is given in m/iatoms oxygen per min. A possible interpretation of these findings was suggested by experi- ments in which arsenate was found to deplete the mitochondria of their endogenous phosphate. When mitochondria labelled with ^'-P were incubated in the presence of arsenate (Table I) an almost complete depletion of mitochondrial phosphate took place within a few minutes. Addition of succinate largely prevented this effect of arsenate. The pre- vention was ascribed to a reincorporation of inorganic phosphate into ATP by way of aerobic phosphorylation, since the oxidation of succinate is only partly uncoupled by arsenate. Addition of respiratory inhibitors such as antimycin A or KCN abolished the succinate effect on the arsenate- induced depletion. Thus the initial low rate of succinate oxidation after preincubation with arsenate was considered to be a consequence of the loss of high energy phosphate from the mitochondria, and the gradual increase in the rate of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original IUB/IUBS International Symposium (1st : 1960 : Stockholm); International Union of Biochemistry; International Union of Biological Sci
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