title: Subcellular location and topography of rat hepatic monoacylglycerol acyltransferase activity.
abstract: Monoacylglycerol acyltransferase activity from suckling rat liver was localized to the microsomal subcellular fraction by differential centrifugation and comparison with the partitioning of selected marker enzymes. Chymotrypsin, pronase, and proteinase K inactivated the monoacylglycerol acyltransferase activity in detergent-disrupted microsomes, but not in intact microsomes, falsely suggesting a lumenal location for the enzyme. The impermeant inhibitors mercury-dextran and 4,4'-diisothiocyano,-2,2'-disulfonic acid stilbene inhibited monoacylglycerol acyltransferase in intact microsomes. These data, as well as the lack of latency and the inability of the substrate palmitoyl-CoA to readily permeate hepatic microsomes from suckling rats, strongly suggest that the enzyme's active site faces the cytosolic surface of the endoplasmic reticulum.
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D000833:Animals, Suckling; D002462:Cell Membrane / Q000201:enzymology; D002463:Cell Membrane Permeability; D010450:Endopeptidases / Q000494:pharmacology; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D000217:Acyltransferases; C021802:2-acylglycerol O-acyltransferase; D010450:Endopeptidases; D000262:Adenylyl Cyclases