Biomaterial Database

Action of a microbial lipase/acyltransferase on phospholipid monolayers. 1991

S Hilton, and J T Buckley

Department of Biochemistry and Microbiology, University of Victoria, British Columbia, Canada.

Vibrio species release a lipase which shares many properties with mammalian lecithin-cholesterol acyltransferase. We have studied the action of the enzyme on phospholipid monolayers. At similar surface pressures, reaction velocities were higher with monolayers of dilauroylphosphatidylcholine than with the corresponding phosphatidylglycerol or phosphatidylethanolamine. The dependence of reaction velocity on molecular density was very similar for phosphatidylcholine and phosphatidylethanolamine monolayers. Lag times were shortest with phosphatidylglycerol at low molecular densities, but maximum velocity was reached at considerably lower densities than with the other two lipids. We have found [Hilton, S., McCubbin, N. D., Kay, C., & Buckley, J.T. (1990) Biochemistry 29, 9072-9078] that nicking of the enzyme with trypsin or other proteases results in an increase in its activity against lipids in membranes. Here we show that trypsin treatment results in a large change in the surface activity of the lipase, allowing it to penetrate monolayers at pressures higher than 40 mN.m-1.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008081	Liposomes	Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.	Niosomes,Transferosomes,Ultradeformable Liposomes,Liposomes, Ultra-deformable,Liposome,Liposome, Ultra-deformable,Liposome, Ultradeformable,Liposomes, Ultra deformable,Liposomes, Ultradeformable,Niosome,Transferosome,Ultra-deformable Liposome,Ultra-deformable Liposomes,Ultradeformable Liposome
D010713	Phosphatidylcholines	Derivatives of PHOSPHATIDIC ACIDS in which the phosphoric acid is bound in ester linkage to a CHOLINE moiety.	Choline Phosphoglycerides,Choline Glycerophospholipids,Phosphatidyl Choline,Phosphatidyl Cholines,Phosphatidylcholine,Choline, Phosphatidyl,Cholines, Phosphatidyl,Glycerophospholipids, Choline,Phosphoglycerides, Choline
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
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
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
D000333	Aeromonas	A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs singly, in pairs, or in short chains. Its organisms are found in fresh water and sewage and are pathogenic to humans, frogs, and fish.
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D014357	Trypsin	A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.	Tripcellim,Trypure,beta-Trypsin,beta Trypsin