Open AccessThe half‐life of human procathepsin S
Author(s) -
Nissler Karl,
Strubel Wolfgang,
Kreusch Stefan,
Rommerskirch Winfried,
Weber Ekkehard,
Wiederanders Bernd
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00547.x
Subject(s) - hek 293 cells , cell culture , cathepsin d , recombinant dna , cathepsin l , cathepsin , biology , microbiology and biotechnology , chemistry , biochemistry , enzyme , gene , genetics
Two processes, synthesis and degradation, contribute to the intracellular concentration of a protein. As most malignant tumors or tumor cell lines show elevated levels of proteinases, we studied the half‐life of a cysteine proteinase, procathepsin S, in order to determine whether tumor cells can regulate their cathepsin concentration via changing the degradation rate of the enzyme. The following procathepsin S species were examined: wild‐type procathepsin S in macrophages, recombinant procathepsin S in human embryonic kidney cells (HEK 293 cells), recombinant nonglycosylated procathepsin S in HEK 293 cells, wild‐type procathepsin S in the established nonsmall cell lung carcinoma cell line 97TM1. The half‐lives of both wild‐type procathepsins S expressed in macrophages and in HEK 293 cells were 1 h, whereas that of procathepsin S in the tumor cell line was 2 h. Nonglycosylated procathepsin S was not processed. The degradation of mature cathepsin S proceeded with a half‐life of 16–18 h. All cell lines studied secreted substantial amounts of procathepsin S into the culture medium. No further maturation of secreted procathepsin S has been observed in the culture medium. We suggest a disturbed sorting mechanism in tumor cells.