Abstract |
The effects of the nonpenetrating amino reactive reagnet 4-acetamido-4'-isothiocyano-stilbene-2-2'-dilsulfonic acid ( SITS) on anion transport ( sulfate, chloride, and inorganic phosphate) were investigated in Ehrlich ascites tumor cells. Short time exposure to SITS produces a reversible inhibition (92%) of sulfate transport. The kinetics of interaction suggest that reversibly bound SITS competitively inhibits sulfate transport, Ki = 3 X 10(-6)M. Incubation of tumor cells with SITS (1 X 10(-4)M) for longer periods of time results in a time dependent irreversible inhibition of sulfate transport which obeys first order kinetics. The rate coefficient for the inactivation process is 0.040 min-1. The kinetics of irreversible inhibition is best explained by the irreversible binding of SITS to the sulfate transport site, and therefore makes SITS a potentially useful probe for the quantiation of these sites in the tumor cell. The lack of effect of irreversibly bound SITS on either chloride or inorganic phosphate transport points to a specificity in the interaction of SITS with the tumor cell membrane, as well as indicating that an alternate pathway exists for the movement of these anions across the membrane.
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Authors | M L Villereal, C Levinson |
Journal | Journal of cellular physiology
(J Cell Physiol)
Vol. 89
Issue 2
Pg. 303-11
(Oct 1976)
ISSN: 0021-9541 [Print] United States |
PMID | 972169
(Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Chlorides
- Phosphates
- Stilbenes
- Sulfates
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Topics |
- Biological Transport, Active
(drug effects)
- Cell Line
- Chlorides
(metabolism)
- Depression, Chemical
- Dose-Response Relationship, Drug
- Kinetics
- Phosphates
(metabolism)
- Stilbenes
(pharmacology)
- Sulfates
(metabolism)
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