Biomaterial Database

Protein-catalyzed exchange of phosphatidylcholine between sonicated liposomes and multilamellar vesicles. 1977

P E DiCorleto, and D B Zilversmit

Phospholipid exchange protein from beef heart or beef liver does not catalyze the transfer of phosphatidylcholine from multilamellar vesicles of phosphatidylcholine. Certain combinations of phospholipids, however, do yield multilamellar vesicles that will exchange phosphatidylcholine with liposomes in the presence of exchange protein. Multilamellar vesicles of phosphatidylcholine:phosphatidylethanolamine:cardiolipin (70:25:5, mol%) can be used in place of mitochondria or erythrocyte ghosts as an improved acceptor particle in the study of liposome structure with phospholipid exchange proteins. These multilamellar vesicles act as a well-defined reservoir of unlabeled phosphatidylcholine with 7% exchangable phospholipid. When the distribution of phosphatidylcholine in liposomes is studied by the exchange protein technique, results can be influence by the choice of phospholipid acceptor particle. With mitochondria as acceptor particle, the percentage of phosphatidylcholine in the outer monolayer of a liposome appears to be 60%, whereas a value of 70% is obtained when multilamellar vesicles are the acceptor. The discrepancy can be explained by a heterogeneity in liposomes prepared by sonication. A size-dependent fusion or adsorption process occurs between liposomes and mitochondria; the very small liposomal vesicles, obtained by gel filtration, combine nearly quantitatively with the natural membrane. This phenomenon is not seen with multilamellar vesicles. Thus by using multilamellar vesicles one obtains a less biased estimate of phospholipid distribution between inner and outer layers of liposomes.

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
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008567	Membranes, Artificial	Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.	Artificial Membranes,Artificial Membrane,Membrane, Artificial
D008931	Mitochondria, Muscle	Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.	Sarcosomes,Mitochondrion, Muscle,Muscle Mitochondria,Muscle Mitochondrion,Sarcosome
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009124	Muscle Proteins	The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.	Muscle Protein,Protein, Muscle,Proteins, Muscle
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
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