title: Localization of the thiorphan-sensitive endopeptidase, termed enkephalinase A, on glial cells.
abstract: Degradation of tritiated Leu-enkephalin was studied in cultures of primary astrocytes from rat brain. The incubation experiments with a cell suspension revealed Tyr as the main tritiated metabolite; however, Tyr-Gly-Gly and Tyr-Gly were detectable as well. Using a crude membrane preparation of the astrocytes, we found about equal amounts of Tyr and Tyr-Gly-Gly but only trace quantities of Tyr-Gly. The production of Tyr was completely inhibited by bestatin, an inhibitor of aminopeptidases, that of Tyr-Gly-Gly by thiorphan, a specific inhibitor of enkephalinase A. The results prove the ability of glial cells to degrade enkephalin by aminopeptidase and a membrane-bound enkephalinase A.
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors; D000818:Animals; D001253:Astrocytes / Q000201:enzymology*; D001921:Brain / Q000166:cytology; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D010450:Endopeptidases / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000378:metabolism; D007700:Kinetics; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D015260:Neprilysin; D011480:Protease Inhibitors; D051381:Rats; D015244:Thiorphan; D008625:Tiopronin / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D011480:Protease Inhibitors; D004743:Enkephalin, Leucine; D015244:Thiorphan; D008625:Tiopronin; D010450:Endopeptidases; D000626:Aminopeptidases; D015260:Neprilysin; D007930:Leucine; C012211:ubenimex