[Lysosomal proteinase activity in the small intestine in postnatal ontogeny].

A lysosomal fraction was isolated from various parts of small intestinal mucose of rats at postnatal periods of growth as well as from adult animals. Activity of marked lysosomal enzymes (acid phosphatase and cathepsins) was 3-fold higher in ileum than the jejunum of young rats at the lactation periods of growth. In adult animals the enzymatic activity was similar both in proximal and distal parts of small intestines. At the postnatal period of growth the lysosomal enzymes appear to carry out a compensatory function, participating in final steps of milk protein digestion.