title: Reconstitution of neutral amino acid transport systems from Ehrlich ascites tumor cells.
abstract: Amino acid transport systems for alanine and leucine were reconstituted into artificial lipid vesicles. Purified plasma membrane vesicles from Ehrlich ascites cells were dissolved in 2% sodium cholate, 1mM dithiothreitol, and 0.5 mM EDTA a mixture that solubilized approximately 50% of the membrane protein. This solubilized protein fraction was further purified by a combination of ammonium sulfate precipitations, gel filtration, and DEAE-cellulose chromatography. A fraction containing approximately 15 Coomassie blue-staining bands on sodim dodecyl sulfate gels was obtained. This material was reconstituted into liposomes, and preliminary results demonstrated transport of alanine and leucine dependent on a sodium gradient. In addition, an electrogenic gradient mediated by valinomycin-induced potassium diffusion seemed to stimulate alanine uptake further.
mesh_terms: D000409:Alanine / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism*; D008081:Liposomes; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism; D051379:Mice
chemical_list: D008081:Liposomes; D008565:Membrane Proteins; D007930:Leucine; D000409:Alanine