A minimum structured adenine nucleotide for ADP/ATP transport in mitochondria.

An ADP analogue, i.e. 3H- or 14C-labeled 5'-diphosphate of 6-(beta-D-ribofuranosyl-methyl)-4-pyrimidinamine, was synthesized, the structure of which was deduced from structure-activity studies on the substrate specificity of the nucleotide-binding center of the inner mitochondrial membrane integrated ADP/ATP carrier protein. Bearing only the minimal but substrate-essential recognition structures, minimum structured ADP (msADP) is bound to the cytosol-facing active center and transported by the highly specific carrier system across the inner mitochondrial membrane.