Biomaterial Database

Nucleoside transport in human erythrocytes. A simple carrier with directional symmetry and differential mobility of loaded and empty carrier. 1982

P G Plagemann, and R M Wohlhueter, and J Erbe

Rapid kinetic techniques were employed to measure the transport of uridine and thymidine in human erythrocytes in zero-trans entry and exist and equilibrium exchange procedures. The kinetic parameters of transport were computed by fitting appropriate integrated rate equations to time courses of transmembrane equilibration of radiolabeled substrate. Transport of uridine and thymidine conformed to the simple carrier model with directional symmetry, but differential mobility of loaded and empty carrier. As was apparent from comparison of zero-trans influx and equilibrium exchange flux, the loaded carrier moved 3 to 18 times faster than the empty carrier in batches of erythrocytes obtained from different individuals. The maximum equilibrium exchange velocities also differed for different batches of erythrocytes. Storage of the cells at 4 degrees C for 4 days or treatment of cells with oxidizing or reducing agents or suspension in hypotonic solutions had no effect on the kinetic properties of the nucleoside transporter. All natural ribo- and deoxyribonucleosides tested when present on the trans side at concentrations well above the Michaelis-Menten constant for transport accelerated the influx and efflux of uridine and inhibited uridine influx when present at these concentrations on the cis side, but nucleobases had no significant effect.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
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
D009705	Nucleosides	Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleoside,Nucleoside Analog,Nucleoside Analogs,Analog, Nucleoside,Analogs, Nucleoside
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill
D013936	Thymidine	A nucleoside in which THYMINE is linked to DEOXYRIBOSE.	2'-Deoxythymidine,Deoxythymidine,2' Deoxythymidine
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014529	Uridine	A ribonucleoside in which RIBOSE is linked to URACIL.	Allo-Uridine,Allouridine,Allo Uridine