. Biological structure and function; proceedings. Biochemistry; Cytology. ASCORBATE-INDUCED LYSIS OF ISOLATED MITOCHONDRIA 55 ascorbate, but the concentrations required are considerably higher. In addition, raising the concentration shortens the lag period. If there is a high concentration which inhibits swelling it was not reached in these experiments. Oxidized glutathione (GSSG) produces a slow steady swel- ling, possibly the result of partial reduction. High concentrations of as- corbate do prevent glutathione induced swelling. Ascorbate Ivsis is more difficult to produce as the concentrati
. Biological structure and function; proceedings. Biochemistry; Cytology. ASCORBATE-INDUCED LYSIS OF ISOLATED MITOCHONDRIA 55 ascorbate, but the concentrations required are considerably higher. In addition, raising the concentration shortens the lag period. If there is a high concentration which inhibits swelling it was not reached in these experiments. Oxidized glutathione (GSSG) produces a slow steady swel- ling, possibly the result of partial reduction. High concentrations of as- corbate do prevent glutathione induced swelling. Ascorbate Ivsis is more difficult to produce as the concentration of the mitochondrial suspension is increased, and unlike phosphate-induced swelling, it is not seen at all in concentrated suspensions. While this could result from rapid exhaustion of ascorbate or Oo, increasing ascorbate in proportion to the mass of mitochondria and thorough oxygenation have 0,5 CONTROLS. 30 " 60 MINUTES Fig. 3. Absorbancy changes due to ascorbate lysis of mitochondria are pre- vented as long as strict anaerobiosis is maintained. Admitting air after 50 min. results in a typical effect of ascorbate. been only partly successful in more concentrated suspensions. Perhaps trace metal binding by the greater mass of protein is involved. Ascorbate induced lysis of the mitochondria requires the presence of some oxygen (Fig. 3). Strict anaerobiosis will prevent lysis for at least 2 hr. If air is admitted after i hr., lysis occurs in the usual characteristic fashion, with the possible exception that the lag period may be a little shorter. In this requirement for oxygen, ascorbate lysis resembles swelling induced by phosphate and many other agents. While swelling with these other agents has been demonstrated to be dependent on endogenous or added substrate in nearly every case, this is not true for ascorbate. Ageing or other treatments of mitochondria which deplete endogenous substrate do not alter the response to ascorbate. Long-term ageing at o^ tends t
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