Transmembrane effects of intracellular chloride on the inhibitory potency of extracellular H/sup 2/DIDS

Journal Article · Tue May 01 04:00:00 EDT 1984 · J. Gen. Physiol.; (United States)

DOI:https://doi.org/10.1085/jgp.83.5.657· OSTI ID:5325698

Furuya, W; Tarshis, T; Law, F Y; Knauf, P A

The ping-pong model for the red cell anion exchange system postulates that the transport protein band 3 can exist in two different conformations, one in which the transport site faces the cytoplasm (E/sub i/) and another in which it faces the outside medium (E/sub o/). This model predicts that an increase in intracellular chloride should increase the fraction of sites in the outward-facing, unloaded form (E/sub o/). Since external H/sub 2/DIDS is a competitive inhibitor of chloride exchange that does not cross the membrane, it must bind only to the E/sub o/ form. Thus, an increase in E/sub o/ should cause an increase in H/sub 2/DIDS inhibition. When intracellular chloride was increased at constant extracellular chloride, the inhibitory potency of H/sub 2/DIDS rose, as predicted by the ping-pong model. This increase was not due to the concomitant changes in intracellular pH or membrane potential. When the chloride gradient was reversed, the inhibitory potency of H/sub 2/DIDS decreased, again in qualitative agreement with the ping-pong model. These data provide support for the ping-pong model and also demonstrate that chloride gradients can be used to change the orientation of the transport protein. 46 references, 8 figures, 3 tables.

• Research Organization: Hospital for Sick Children, Toronto, Ontario
• OSTI ID: 5325698
• Journal Information: J. Gen. Physiol.; (United States), Journal Name: J. Gen. Physiol.; (United States) Vol. 83; ISSN JGPLA
• Country of Publication: United States
• Language: English

Related Subjects

550500* -- Metabolism
551000 -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MODELS
CELL CONSTITUENTS
CELL MEMBRANES
CHLORIDES
CHLORINE COMPOUNDS
CONFORMATIONAL CHANGES
ENZYME INHIBITORS
HALIDES
HALOGEN COMPOUNDS
KINETICS
MEMBRANE PORES
MEMBRANE TRANSPORT
MEMBRANES
METABOLISM
REACTION KINETICS
RESPONSE MODIFYING FACTORS
TESTING
VALIDATION