We often discuss the importance of the mitochondrial adenine nucleotide exchanger; indeed, many suggest it is rate limiting for oxidative phosphorylation. But its function has no effect on total mitochondrial nucleotide content.
What is your view of the control of total mitochondrial adenine nucleotide content (ATP + ADP + AMP)? Are isolated mitochondria capable of purine biosynthesis?
If mitochondria can only exchange one mitochondrial ATP for one cytosolic ADP, then there is nothing a mitochondrion can do to increase or decrease the sum of mitochondrial ATP+ADP+AMP. This seems paradoxical. Where does a mitochondrion get its initial allocation of adenine nucleotides?