Cytochalasin B binding to Ehrlich ascites tumor cells and its relationship to glucose carrier

摘要: Abstract Cultured Ehrlich ascites tumor cells equilibrate d -glucose via a carrier mechanism with K m and V of 14 mM 3 μmol/s per ml cells, respectively. Cytochalasin B competitively inhibits this carrier-mediated glycose transport an inhibition constant ( i ) approx. 5·10 −7 M. E does not inhibit function. With cytochalasin concentrations up to 1·10 −5 M, the range where develops practical completion, three discrete binding sites, namely L, M H, are distinguished. The at L site shows dissociation -6 represents about 30% total cell (8·10 6 molecules/cell), is sensitively displaced by but -glucose, located in cytosol. 4–6·10 60% saturable (14·10 specifically displacement 15 mM, l insensitive E. sites membrane-bound extractable Triton X-100 EDTA alkaline pH. H 2–6 · 10 −8 less than 10% (2 affected either glucose or non-cytosol origin. It concluded that responsible for unique among other animal its high content site. Approx. 16-fold purification has been achieved.