Enzyme der Vakuolen aus Wurzelzellen von Maiskeimlingen. Ein Beitrag zur funktionellen Bedeutung der Vakuole bei der intrazellulären Verdauung

The isolation of vacuoles from rootlets of corn seedlings based on the slicing and chopping of the plasmolized tissue is described. The isolated vacuoles have densities higher than 1,029 g cm ; in the centrifugal field they rapidly move centripetally if the extracts are brought to a density of 1,185 g cm by the addition of 30% of “Urografine”. Thus a simple separation of isolated vacuoles from the extracts could be achieved. The following hydrolytic enzymes have been localized in isolated vacuoles: protease, RNase, DNase, phosphatase and two different unspecific esterases. Furthermore two transaminases, aspartate and alanine-aminotransferase and two oxyreductases cytochrome-c-reductase and diaphorase are present in preparations of isolated vacuoles. The absence of mitochondrial enzymes and of enzymes known to be localized in the groundplasm indicated the purity of the preparations of vacuoles. It is concluded that the vacuoles of higher plant cells represent organelles in which the processes of intracellular digestion take place.