Sensitivity Of The Mitochondrial Unspecific Channel Of Saccharomyces Cerevisiaeto Butane-1,4-Bisphosphate, A Competitive Inhibitor Of Fructose-1,6-Bisphosphate-Aldolase.

Fructose-1,6-bisphosphate (F1,6BP) promotes closure ofthe S. cerevisiae mitochondrial unspecific channel (ScMUC) enhancing coupling of oxidative phosphorylation and probably contributing to the Crabtree effect. In contrast the closely related glucose-6-phosphate (G6P) opens ScMUC. In order to understand the putative effects of F1,6BPon the mitochondrial unspecific channel, butane-1,4-bisphosphate (B1,4BP), a non-me-tabolizable, competitive inhibitor of F1,6BP-aldolase, was synthesized and tested on isolated mitochondria. B1,4BP closed ScMUC and its effects were reverted by increasing concentrations of G6P. Thus, in regard to its effects on ScMUC, and most likely due to structural similarities allowing it to bind to the same sites, B1,4BP is an analog of F1,6BP.