[Lysosomal hydrolases of various rat organs in the process of cell nutrition]

Activity of lysosomal proteinases cathepsins A, B, C, D, H and L was studied in liver, kidney, spleen, thymus, heart, skeletal muscle and brain tissues of rats, maintained on full value diet, on a diet free of proteins and on the diet enriched with methionine. Distinctly dissimilar reactions of thiol-dependent proteinases was detected in liver, heart tissues and skeletal muscles as compared with the reaction of cathepsins A and D; activity of cathepsins B, H and L was decreased 1.5-2-fold in the animal groups maintained on diets both free of proteins and enriched with methionine. The data obtained suggest that concentration of endogenous inhibitors of lysosomal thiol-dependent proteinases rather than content of SH-groups in tissues was responsible for alterations of their activity under conditions of protein starvation.