Biomaterial Database

Asymmetric binding of cytochrome b5 to the membrane of human erythrocyte ghosts. 1977

K I Enomoto, and R Sato

The intact, amphipatic form of cytochrome b5 could bind to unsealed ghosts, but not to resealed ghosts, suggesting that the cytochrome could bind only to the inner (cytoplasmic) surface of the ghost membrane. This was further confirmed by the finding that the cytochrome could bind to closed, inside-out vesicles prepared from the ghosts. This asymmetric binding was not due to the exclusive localization of sialic acid and sugar chains on the outer surface of the ghosts membrane, because the cytochrome could not bind to ghosts even after enzymatic removal of these components. Although liposomes consisting of phosphatidylcholine or both phosphatidylcholine and sphingomyelin could effectively bind the cytochrome, this binding capacity was progressively decreased as increasing amount of cholesterol was included in the composition of phosphatidylcholine liposomes. Removal of cholesterol from resealed ghosts by incubation with egg phosphatidylcholine liposomes resulted in the binding of cytochrome b5 to the outer surface of the treated ghosts. The possibility is discussed that the asymmetric binding is due to preferential localization of cholesterol in the outer leaflet of the lipid bilayer that constitutes the ghost membrane.

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
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
D009439	Neuraminidase	An enzyme that catalyzes the hydrolysis of alpha-2,3, alpha-2,6-, and alpha-2,8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. (From Enzyme Nomenclature, 1992)	Sialidase,Exo-alpha-Sialidase,N-Acylneuraminate Glycohydrolases,Oligosaccharide Sialidase,Exo alpha Sialidase,Glycohydrolases, N-Acylneuraminate,N Acylneuraminate Glycohydrolases,Sialidase, Oligosaccharide
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
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D003580	Cytochromes	Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.	Cytochrome
D004910	Erythrocyte Membrane	The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.	Erythrocyte Ghost,Red Cell Cytoskeleton,Red Cell Ghost,Erythrocyte Cytoskeleton,Cytoskeleton, Erythrocyte,Cytoskeleton, Red Cell,Erythrocyte Cytoskeletons,Erythrocyte Ghosts,Erythrocyte Membranes,Ghost, Erythrocyte,Ghost, Red Cell,Membrane, Erythrocyte,Red Cell Cytoskeletons,Red Cell Ghosts
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle