Differential competitive inhibition of a cell surface protease on normal epithelial cells and carcinoma cells of the colon.
The cell surfaces of normal colonic epithelial cells and colonic carcinoma cells both possess a protease referred to as guanidinobenzoatase (GB). Previous studies have shown that these cells possess two distinct isoenzymic forms of GB which could be distinguished by their selective recognition of cytoplasmic protein inhibitors of GB. In the present study we have used competitive inhibitors of GB to demonstrate the differential inhibition of the GB on normal colonic epithelial cells whilst the GB on colonic carcinoma cell surfaces remains active. The enzymic status of GB on these cells has been determined by challenging the treated cells in frozen sections with a second fluorescent inhibitor, followed by fluorescence microscopic analysis.
Department of Biochemistry and Molecular Biology, School of Biological Sciences, University of Manchester, U.K.
F S
FS
Steven
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M
Anees
I C
IC
Talbot
D000585:Aminacrine / Q000378:metabolism; D001485:Basement Membrane / Q000201:enzymology; D001667:Binding, Competitive; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism / Q000494:pharmacology*; D003106:Colon / Q000201:enzymology*; D003110:Colonic Neoplasms / Q000201:enzymology*; D010450:Endopeptidases / Q000378:metabolism / Q000494:pharmacology*; D004848:Epithelium / Q000201:enzymology; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D012016:Reference Values
D007527:Isoenzymes; D008565:Membrane Proteins; D000585:Aminacrine; D002265:Carboxylic Ester Hydrolases; C037288:guanidinobenzoate esterase; D010450:Endopeptidases