Abstract
In experiments carried out with sucrose-isolated rat liver mitochondria, C(14)-sucrose seems to penetrate most of the mitochondrial space rapidly, whereas it seems to penetrate the remainder relatively slowly. However, taking into account the wide size distribution found in isolated preparations, these rates have been found consistent with the kinetics expected from the assumption of a single compartment per mitochondrion. These data cannot be readily interpreted on the basis of two mitochondrial spaces, one highly permeable, and another relatively impermeable to sucrose.