title: Nonspecific esterase activity expressed in Weibel-Palade bodies of cloned guinea pig aortic endothelial cells.
abstract: We studied the localization of nonspecific esterase activities in cloned guinea pig aortic endothelial cells using ultrastructural cytochemistry. Weibel-Palade bodies (WPB), which are known to contain von Willebrand protein, were positive for esterase, defining a heretofore unrecognized activity of these organelles. Esterase activity was also found localized to the external surface of the plasma membrane, to cytoplasmic lipid bodies, and to the outer (cytoplasm-facing) surface of certain membrane-bound cytoplasmic vacuoles. Localization of esterase activity to these four discrete sites probably reflects the presence of a number of endothelial cell enzymes capable of hydrolyzing alpha-naphthyl acetate or butyrate. The physiological substrate and biological function of these enzyme activities are not presently understood.
mesh_terms: D000818:Animals; D001011:Aorta / Q000648:ultrastructure; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D002999:Clone Cells / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D004727:Endothelium / Q000648:ultrastructure*; D004950:Esterases / Q000378:metabolism*; D006168:Guinea Pigs; D006651:Histocytochemistry; D050356:Lipid Metabolism; D008854:Microscopy, Electron; D009940:Organoids / Q000201:enzymology*; D014617:Vacuoles / Q000201:enzymology
chemical_list: D004950:Esterases