A proteolytic activity enhanced by arsenite in Chinese hamster ovary cells: possible involvement in arsenite-induced cell killing.
Treatment of Chinese hamster ovary (CHO-K1) cells with 10 microM sodium arsenite for 24 h resulted in enhancement of a proteolytic activity toward the chromogenic substrate CBZ-Phe-Arg-AMC. Presence of dithiothreitol and a pH between 4 and 6 were required for displaying its full hydrolytic activity. According to its substrate- and inhibitor-specificity, this arsenite-induced proteolytic activity was very similar to lysosomal cathepsin B. Arsenite cytotoxicity was further shown to be partially prevented by inhibitors that inhibited the arsenite-induced protease, such as antipain and chymostatin, but not by protease inhibitors without inhibitory effects on the arsenite-induced protease. Our present results suggest that the arsenite-induced protease activity may be involved in arsenite's killing effects.
Yih
L H
LH
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China.
Lee
T C
TC
D000818:Animals; D018053:Arsenites / Q000494:pharmacology*; D016466:CHO Cells / Q000187:drug effects / Q000201:enzymology*; D016923:Cell Death / Q000187:drug effects*; D003374:Coumarins / Q000378:metabolism; D006224:Cricetinae; D004151:Dipeptides / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism*; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000494:pharmacology; D017670:Sodium Compounds / Q000494:pharmacology*; D013379:Substrate Specificity
D018053:Arsenites; D003374:Coumarins; D004151:Dipeptides; D005456:Fluorescent Dyes; D011480:Protease Inhibitors; D017670:Sodium Compounds; C017947:sodium arsenite; C021159:benzyloxycarbonyl-phenylalanylarginine-4-methylcoumaryl-7-amide; D010450:Endopeptidases; D004229:Dithiothreitol