Supramolecular assembly of metabolic enzymes has been studied both in vivo and in vitro for nearly a decade. Experimental evidence has suggested a close relationship between enzymatic activity and enzyme assembly/disassembly. However， most cases were studied with the cytosolic enzymes. Here， I report the evidence for a mitochondrial enzyme with its ability in forming visible intracellular structures. By removing the mitochondrial targeting sequence， yeast mitochondrial enzyme aldehyde dehydrogenase (Ald4p) exhibits reversible supramolecular assembly in the cytoplasm， thus creating a useful system for further characterization of the regulatory factors that modulate the assembly/disassembly of this mitoch... More