Biomaterial Database

Effects of pH on 5-methyltetrahydrofolic acid transport in human erythrocytes. 1982

R F Branda, and N L Nelson

We measured the effects of external pH on influx, efflux and net steady-state levels for 14CH3H4PteGlu1. Initial rates of uptake were inversely proportional to external pH. Lowering the pH of the suspending medium increased influx by enhancing the affinity of the carrier: the apparent Km values at pH 6, 7.2 and 8.1 were 0.14, 0.25 and 0.63 microM respectively. In contrast, Vmax was independent of external pH. Efflux rate constants at pH 6, 7.5 and 8.5 were 0.034, 0.059 and 0.067/min respectively. consequently, lowering the external pH increased steady-state levels of 14CH3H4PteGlu1.

UI	MeSH Term	Description	Entries
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
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D013763	Tetrahydrofolates	Compounds based on 5,6,7,8-tetrahydrofolate.