title: In vitro studies on origin and site of action of enzyme activity responsible for conversion of human proapoprotein A-I into apoprotein A-I.
abstract: Human hepatocellular carcinoma cells (Hep G2) were shown to secrete apo A-I as a proprotein . No apo A-I synthesis could be detected with endothelial cells from human umbilical cord veins. Conversion of proapo A-I into apo A-I is a slow (of the order of hours) process, mediated by a Ca2+/Mg2+-dependent enzyme which is present on the surface of plasma lipoprotein particles, endothelial cells and Hep G2 cells, and is probably synthesized by Hep G2 cells.
mesh_terms: D016632:Apolipoprotein A-I; D001053:Apolipoproteins / Q000378:metabolism*; D001054:Apolipoproteins A; D001769:Blood; D002118:Calcium / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000201:enzymology*; D002460:Cell Line; D004727:Endothelium / Q000201:enzymology; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D008074:Lipoproteins / Q000378:metabolism; D008113:Liver Neoplasms; D008274:Magnesium / Q000378:metabolism; D008970:Molecular Weight; D011247:Pregnancy; D011498:Protein Precursors; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D016632:Apolipoprotein A-I; D001053:Apolipoproteins; D001054:Apolipoproteins A; D008074:Lipoproteins; D011498:Protein Precursors; D008274:Magnesium; D002118:Calcium