Biomaterial Database

Effect of phospholipase C hydrolysis of membrane phospholipids on acyltransferase systems in rat liver microsomes. 1976

S Sonoki, and H Ikezawa

Three kinds of phospholipase C [EC 3.1.4.3] were used to selectively hydrolyze phospholipids in rat liver microsomes, and their effects on the acyl-CoA: glycerophosphate and acyl-CoA: lysophospholipids acyltransferase systems were examined. The glycerophosphate acyltransferase [EC 2.3.1.15] system was inactivated rapidly by treatment with phospholipase C of Ps. aureofaciens or B. cereus and the loss of activity paralleled the degradation of phosphatidylcholine and phosphatidylethanolamine. The 1-acylglycerylphosphorylcholine acyltransferase [EC 2.3.1.23] system was only partially inactivated under the same conditions, whereas the 1-acylglycerophosphate acyltransferase [EC 2.3.1.51] system retained most of its activity even when more than 95% of phosphatidylcholine and phosphatidylethanolamine had been hydrolyzed. The results demonstrate the heterogeneity of acyltransferase systems with respect to their dependence on the intact membrane phospholipids. Hydrolysis of more than 80% of phosphatidylinositol by phosphoinositidase of B. cereus did not significantly affect these acyltransferase systems. The specificity for various acyl-CoA's of 1-acylglycerophosphate acyltransferase in microsomes treated with phospholipase C of Ps. aureofaciens was apparently different from that in untreated microsomes, while the specificity of 1-acylglycerylphosphorylcholine acyltransferase was unchanged. Saturation profiles of the acceptors were significantly different between the acyltransferase systems in phospholipase C-treated and untreated microsomes. These results suggest that 1-acylglycerophosphate and 1-acylglycerylphosphorylcholine acyltransferase systems do not require specific phospholipids such as phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol for their catalytic activities, but the integrity of these phospholipids is necessary for the proper functioning and stability of the enzymes.

UI	MeSH Term	Description	Entries
D008243	1-Acylglycerophosphocholine O-Acyltransferase	An enzyme localized predominantly within the plasma membrane of lymphocytes. It catalyzes the transfer of long-chain fatty acids, preferentially unsaturated fatty acids, to lysophosphatides with the formation of 1,2-diacylglycero-3-phosphocholine and CoA. EC 2.3.1.23.	1-Acylglycerophosphocholine Acyltransferase,Acyl CoA Lysolecithin Acyltransferase,Lysolecithin Acyltransferase,Acyl-CoA-1-Acylglycero-3-Phosphocholine-O-Acyltransferase,Lysophosphatidylcholine Acyltransferase,Lysophosphatidylcholine-Palmitoyl CoA Acyltransferase,Lysophospholipid Acyltransferase,1 Acylglycerophosphocholine Acyltransferase,1 Acylglycerophosphocholine O Acyltransferase,Acyl CoA 1 Acylglycero 3 Phosphocholine O Acyltransferase,Acyltransferase, 1-Acylglycerophosphocholine,Acyltransferase, Lysolecithin,Acyltransferase, Lysophosphatidylcholine,Acyltransferase, Lysophosphatidylcholine-Palmitoyl CoA,Acyltransferase, Lysophospholipid,CoA Acyltransferase, Lysophosphatidylcholine-Palmitoyl,Lysophosphatidylcholine Palmitoyl CoA Acyltransferase,O-Acyltransferase, 1-Acylglycerophosphocholine
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D010740	Phospholipases	A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.	Lecithinases,Lecithinase,Phospholipase
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D011549	Pseudomonas	A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.	Chryseomonas,Pseudomona,Flavimonas
D005228	Fatty Acids, Essential	Long chain organic acid molecules that must be obtained from the diet. Examples are LINOLEIC ACIDS and LINOLENIC ACIDS.	Acids, Essential Fatty,Essential Fatty Acids
D005992	Glycerol-3-Phosphate O-Acyltransferase	An enzyme that transfers acyl groups from acyl-CoA to glycerol-3-phosphate to form monoglyceride phosphates. It acts only with CoA derivatives of fatty acids of chain length above C-10. Also forms diglyceride phosphates. EC 2.3.1.15.	Glycerolphosphate Acyltransferase,Stearyl-CoA Glycerophosphate Transstearylase,Acyl-CoA Sn-Glycerol-3-Phosphate-O-Acyltransferase,Glycerophosphate Acyltransferase,Acyl CoA Sn Glycerol 3 Phosphate O Acyltransferase,Acyltransferase, Glycerolphosphate,Acyltransferase, Glycerophosphate,Glycerol 3 Phosphate O Acyltransferase,Glycerophosphate Transstearylase, Stearyl-CoA,O-Acyltransferase, Glycerol-3-Phosphate,Sn-Glycerol-3-Phosphate-O-Acyltransferase, Acyl-CoA,Stearyl CoA Glycerophosphate Transstearylase,Transstearylase, Stearyl-CoA Glycerophosphate
D000217	Acyltransferases	Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.	Acyltransferase
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia