Respiration-stimulated activation of deoxyribonuclease I associated with mitochondria

Abstract

The effect of respiration and calcium transport in the liver mitochondria on activation of DNase I associated with the organelles was investigated. It was shown that 96% of the total activity of this enzyme in the mitochondria is in a latent state. Aeration of a suspension of mitochondria leads to a sharp rise in its activity. Activation of DNase I is inhibited by the addition of EGTA and stimulated in mitochondria releasing calcium. The pH optimum of EGTA-inhibited activation of DNase I was shown to be 8.0. It is concluded that activation of this enzyme depends on the state of cellular energetics. It is suggested that a role is played by mitochondrial phospholipase A, activated during release of calcium from the mitochondria in the process of activation of DNase I.