title: Clinical experience with the testing of serum proteinase activity by cathepsin B-like sensitive amino acid derivatives of 7-amino-4-methylcoumarine.
abstract: The proteolytic activity of serum against two synthetic polypeptide substrates conjugated with 7-amino-4-methylcoumarine which are known to be highly specific substrates for lysosomal cathepsin B-like cysteine proteinase, was studied in normal individuals and in patients with breast and colorectal cancer. The results showed that both substrates are cleaved in different ways and their hydrolysis is very poorly sensitive to inhibitors of cysteine proteinases. On the other hand, cleavage is intensively inhibited by disodium-EDTA which is known as an activator of cysteine proteinases. This indicates that lysosomal conditions are quite different from serum which is an unstable mixture of various enzymes and their substrates. It was also demonstrated that hydrolysis of the tested substrates is not probably realized by cysteine proteinases but it can be performed by cooperation of other serum proteinases. Moreover, our results confirmed that serum activity of these enzymes can be significantly higher in patients with breast cancer, particularly with metastasis, than in healthy women. A slight insignificant increase was observed also in patients with colorectal cancer.
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology; D002401:Cathepsin B / Q000097:blood*; D003110:Colonic Neoplasms / Q000201:enzymology / Q000473:pathology; D003374:Coumarins; D003545:Cysteine; D004492:Edetic Acid; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007202:Indicators and Reagents; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010447:Peptide Hydrolases / Q000097:blood*; D011480:Protease Inhibitors / Q000494:pharmacology; D012004:Rectal Neoplasms / Q000201:enzymology
chemical_list: D003374:Coumarins; D007202:Indicators and Reagents; D011480:Protease Inhibitors; D004492:Edetic Acid; D010447:Peptide Hydrolases; D002401:Cathepsin B; D003545:Cysteine; C028743:7-amino-4-methylcoumarin