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Electrogenic H(+)-regulated sulfate-chloride exchange in lobster hepatopancreatic brush-border membrane vesicles.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Cattey, M. A. Gerencser, Georpe A. Ahearn, Gregory A. |
| Copyright Year | 1992 |
| Abstract | Transport of [35S]sulfate by brush-border membrane vesicles (BBMV) of lobster (Homarus americanus) hepatopancreas was stimulated by an outwardly directed chloride gradient. In contrast, sulfate uptake was not enhanced by inwardly directed Na+ or K+ transmembrane gradients. An inside-positive membrane potential (valinomycin and K+) stimulated SO4(2-)-Cl- exchange, whereas an inside-negative membrane potential was inhibitory. Sulfate-sulfate exchange was not affected by alterations of transmembrane potential. An inwardly directed proton gradient, or the presence of low bilateral pH, enhanced SO4(2-)-Cl- exchange, but the H+ gradient alone did not stimulate sulfate uptake in chloride-equilibrated BBMV or in vesicles lacking internal Cl-. The stilbenes 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) strongly inhibited SO4(2-)-Cl- exchange. Sulfate influx occurred by a combination of carrier-mediated transfer, exhibiting Michaelis-Menten kinetics, and nonsaturable "apparent diffusion." 36Cl- influx into sulfate-loaded BBMV was stimulated by an inside-negative transmembrane potential compared with short-circuited vesicles. These results suggest that sulfate-chloride exchange in hepatopancreatic BBMV occurred by an electrogenic carrier mechanism exhibiting a 1:1 flux ratio that was modulated by internal and external H(+)-sensitive regulatory sites. The role of this antiport process in anion secretion is discussed. |
| Starting Page | 109 |
| Ending Page | 109 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://ajpregu.physiology.org/content/ajpregu/262/2/R255.full.pdf |
| PubMed reference number | 1539734v1 |
| Volume Number | 262 |
| Issue Number | 2 |
| Part | 2 |
| Journal | The American journal of physiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Ampulla of Vater Anions Chloride Ion Exhibits as Topic Gradient Hepatopancreas Membrane Potentials Potassium Protons Sodium Stilbenes Thioctic Acid Tissue membrane Valinomycin Vesicle (morphologic abnormality) antiporter activity viral capsid secondary envelopment |
| Content Type | Text |
| Resource Type | Article |
