Premium
The interaction of chloride with the sulfate transport system of ehrlich ascites tumor cells
Author(s) -
Levinson Charles
Publication year - 1976
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040870212
Subject(s) - sulfate , ascites , chloride , ehrlich ascites , chemistry , tumor cells , biochemistry , cancer research , biology , medicine , organic chemistry
The effect of Cl − on SO 4 −2 efflux was studied in both Cl − ‐containing and Cl − ‐free ascites tumor cells loaded with 35 SO 4 −2 to test the hypothesis that Cl − ‐SO 4 −2 exchange is mediated by the same mechanism responsible for SO 4 −2 ‐self exchange. The addition of Cl − ‐free, 35 SO 4 −2 loaded cells to a SO 4 −2 ‐free, Cl − medium results in: (1) SO 4 −2 efflux that is dependent on the extracellular Cl − concentration (Km = 4.85 mM; k e = 0.048 min −1 at 50 mM Cl − ) and (2) net Cl − ‐uptake that exceeds SO 4 −2 loss. Both SITS (4‐acetamido‐4′‐isothiocyanostilbene‐2,2′‐disulfonate) and ANS (1‐anilino‐8‐napthalene sulfonate) inhibit SO 4 −2 efflux but are without effect on Cl − uptake. The addition of Cl − ‐containing, 35 SO 4 −2 loaded cells to a SO 4 −2 ‐free, C1 − medium results in: (1) a slight gain in cellular Cl − and (2) k efor SO 4 −2 efflux identical to that for Cl − ‐free cells. The results are compatible with the suggestion that: (1) Cl − interacts with a membrane component responsible for transmembrane SO 4 −2 movement; (2) Cl − interaction stimulates the rate of unidirectional SO 4 −2 efflux from cells initially free of Cl − as well as the rate of SO 4 −2 turnover in cells maintained in the steady state with respect to Cl − and SO 4 −2 ; and (3) in the case of cells initially free of Cl − , the Cl − ‐SO 4 −2 pathway represents only a small fraction of the total unidirectional Cl − ‐influx the remainder being compatible with the electroneutral accumulation of NaCl and KCl.