Cathepsin B and L activity in the serum during the human aging process: cathepsin B and L in aging

Cathepsin B and L are active in several physiological processes that occur in the human body. Their synthesis and activity is detectable in several tissues and processes, including skin hyperkeratosis, insemination, and embryonic development. Proteolytic enzymes are very important cellular constituents and have been the subject of much research. The enzymes are in the limelight of scientists first of all as ECM degradation factors. Most publications describe proteolytic enzymes as tumor and metastasis factors. These proteases also have a central function as apoptosis factors. The aim of this study was to evaluate correlations between age and the enzymatic activities of the proteolytic enzymes cathepsin B and L together. This research was conducted using blood samples provided by healthy people (n=60, 30 men and 30 women). Subjects were subdivided into groups with respect to age: young (about 20 years old, n=20), middle age (about 50 years old, n=20), and elderly (about 80 years old, n=20). Fluorometric assay was used to determine proteolytic enzyme activity. Cathepsin B and L activity was measured as a total activity. The activity of cathepsin B and L significantly increases with age.