[Lysosomal proteolytic system of eukaryotes in the process of phylogenetic development]

Significant differences have been found between the spectra of lysosomal proteinases in animals from different taxonomic groups, i.e. Hydra oligactis. Digesia tigrina, Anodonta cygnea, Salmo irideus, Rana ridibunda, Gallus bankiva, Rattus norvegicus. In lower organisms, which exhibit mainly intracellular digestion (Hydrozoa, Turbellaria), lysosomal proteolytic system is presented almost exclusively by cathepsin D, whereas in higher animals the quota of cathepsin D activity decreases (4-10 times) together with the increase in the activity of other proteinases (cathepsins A, B1 and C). The increase in the proportion of proteinases with a higher substrate specificity presumably reflects evolutionary specialization of cellular lysosomal apparatus.