[Purification of leucine-endopeptidase from Saccharomyces cerevisiae inner mitochondrial membrane]

Several proteolytic activities have been extracted from isolated yeast mitochondrial inner membranes, in the presence of Tween 20. Absence of matrix and cytoplasmic contamination has been checked. A leucine-endopeptidase has been purified to homogeneity. It has an apparent molecular mass of 66 kDa and a pHi near 8.6. It is a serine-protease, which hydrolyses synthetic polypeptides whose leucine carboxylic group is engaged, as well as various macromolecular proteins; its optimal pH is 7.2.