AN ASSAY OF ADENINE NUCLEOTIDE TRANSLOCASE ACTIVITY

摘要

A method is disclosed herein to measure the activity of the adenine nucleotide translocase (ANT) in membrane compartments, preferably mitochondria. In the method of the invention, membrane compartments comprising the ANT protein are incubated in a medium comprising at least free Mg2+ ions, ATP and ADP, and the rate of ATP/ADP translocation is assessed by meas-uring a change in free Mg2+ ion concentration [Mg2+] in the medium. In a preferred embodiment upon addition of ADP oxidative phosphorylation is initiated, resulting in the exchange of ADP in the extramitochondrial compartment with ATP. ANT activity is calculated from the rate of change in free [Mg2+] using standard binding equations. The method of the invention is useful to quantify ANT protein activity or content, and it can also be combined with other ANT assays or simultaneous assessment of additional mitochon-drial parameters.