Detection of dipeptidyl peptidase IV in glioma C6 and neuroblastoma SK-N-SH cell lines.
The dipeptidyl peptidase IV (DPP-IV) activity of the rat glioma cell line C6 and the human neuroblastoma cell line SK-N-SH was investigated. DPP-IV fluorescent substrate was cleaved by both cell lines. The pH reaction optimum determined was typical for DPP-IV described in other cell models. The reaction was inhibited by specific inhibitors diprotins A and B. Enzyme activity was localized, both on the cell surface and intracellularly. Most of the DPP-IV activity was membrane bound. However, soluble intra-cellular activity was found in both cell lines. Secreted activity was not detected in either cell line. In the C6 line, but not in the SK-N-SH line, we demonstrated depression of the ratio of cell surface to total cell DPP-IV activity at higher cell densities, indicating possible enzyme redistribution during cell growth in culture. Identification of DPP-IV activity is the first step in our study of the role of DPP-IV in the neural system.
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First Department of Medical Chemistry and Biochemistry, First Medical Faculty, Charles University, Czech Republic.
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D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D003374:Coumarins; D004151:Dipeptides; D018819:Dipeptidyl Peptidase 4 / Q000032:analysis / Q000378:metabolism*; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors; D005456:Fluorescent Dyes; D005910:Glioma / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009447:Neuroblastoma / Q000201:enzymology*; D009842:Oligopeptides / Q000494:pharmacology; D051381:Rats; D014407:Tumor Cells, Cultured
D003374:Coumarins; D004151:Dipeptides; D005456:Fluorescent Dyes; D009842:Oligopeptides; C057970:glycylprolyl-4-methylcoumaryl-7-amide; C041445:diprotin A; C041446:diprotin B; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4