Studies on 5'-methylthioadenosine uptake by human erythrocytes.
The transport of 5'-methylthioadenosine across plasma membrane of human erythrocytes occurs by a carrier-mediated mechanism displaying a Km of congruent to 3 mM and a Vmax of congruent to 600 pmol/10(6) cells/min. Phosphate-depleted erythrocytes were employed to distinguish between 5'-methylthioadenosine transport and metabolic trapping. In phosphate medium, where 5'-methylthioadenosine phosphorylase is operative, the uptake of radioactivity increases over the theoretical calculated equilibrium owing principally to conversion of the molecular into 5-methylthioribose-1-phosphate. Newly developed HPLC techniques have been applied to analyze intracellular 5'-methylthioadenosine and its metabolites after exposure of the erythrocytes to [14C]-labelled 5'-methylthioadenosine.
D000241:Adenosine / Q000031:analogs & derivatives* / Q000097:blood; D001693:Biological Transport, Active; D002851:Chromatography, High Pressure Liquid; D003839:Deoxyadenosines; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D010710:Phosphates / Q000097:blood; D013872:Thionucleosides / Q000097:blood*
D003839:Deoxyadenosines; D010710:Phosphates; D013872:Thionucleosides; C008500:5'-methylthioadenosine; D000241:Adenosine