[On the age dependence of the intracellular proteolysis (author's transl)]

We report the age dependent changes of the proteolytic capacity of the rat liver at pH 3.0 and pH 6.0. The total proteolytic activity increases during the whole cycle. During the weanling period the specific activity (mug substrate split x min-1 X mg liver protein-1) rises up to values about 30% higher than those of the remaining lifetime. We found the specific activity in old male animals (18 months) to be lower than in younger ones (5 months). These findings are correct for the liver homogenate as well as for the cell fractions.