Relationship between the Rate of Citrulline Synthesis and Bulk Changes in the Intramitochondrial ATP/ADP Ratio in Rat‐Liver Mitochondria

Open Access
Publisher Website
Google Scholar
Abstract
The relationship between intramitochondrial and extramitochondrial ATP‐utilizing systems and the intramitochondrial ATP/ADP ratio was studied in isolated rat‐liver mitochondria. Citrulline synthesis was used as an intramitochondrial ATP‐utilizing system, and glucose‐6‐phosphate synthesis as an extramitochondrial ATP‐utilizing system. The intramitochondrial ATP/ADP ratio was manipulated in three ways: with succinate and different concentrations of malonate and/or hexokinase; with 2‐oxoglutarate (plus oligomycin) and different concentrations of hexokinase; and with added ATP in uncoupled mitochondria (oligomycin present). Under all conditions used, citrulline synthesis was strictly correlated with the bulk intramitochondrial ATP/ADP ratio. The curve relating citrulline synthesis and intramitochondrial ATP/ADP was shifted towards lower ATP/ADP ratios when the activity of carbamoyl‐phosphate synthetase was enhanced by increasing the mitochondrial content of N‐acetylglutamate. It is concluded that under the experimental conditions used the intramitochondrial adenine nucleotides behave as a homogeneous pool.

This publication has 36 references indexed in Scilit: