Conversion of cathepsin E to enzymatic unstable form in gastric cancer cells.
A new acid proteinase in human gastric cancer, named medium moving proteinase (Med.P), was found also in a gastric cancer transplanted into nude mouse. However, Med.P disappeared when the samples prepared from gastric cancer tissues were left for over 4 weeks at -80 degrees C, whereas the activity of cathepsin E (CE) increased. When these samples were reduced by dithiothreitol (DTT), Med.P appeared again and the CE activity decreased. These phenomena, revealed by electrophoretic analyses, indicated that Med.P is a monomeric form of CE (mono-CE). At weakly alkaline pH and after heating, mono-CE appeared to be more unstable than CE. These results indicated that CE assume an enzymatically unstable monomeric form in cancer cells.
Aoki
T
T
Department of Biochemistry, Faculty of pharmaceutical Sciences, Health Sciences University of Hokkaido, Japan.
Takasaki
T
T
Furukawa
T
T
Morikawa
J
J
Yano
T
T
Watabe
H
H
D000818:Animals; D020059:Cathepsin E; D002403:Cathepsins / Q000378:metabolism*; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D013274:Stomach Neoplasms / Q000201:enzymology*; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D013439:Sulfhydryl Reagents; D002403:Cathepsins; D010450:Endopeptidases; D020059:Cathepsin E; D004229:Dithiothreitol