Sulfate transport in apical membrane vesicles isolated from tracheal epithelium
Sulfate uptake in apical membrane vesicles isolated from bovine tracheal epithelium is shown to occur into an osmotically sensitive intravesicular space, via a carrier-mediated system. This conclusion is based on three lines of evidence: 1) saturation kinetics: 2) substrate specificity; and 3) inhibition by the anion transport inhibitors SITS and DIDS. The affinity of the transport system is highest in low ionic strength media and decreases in the presence of gluconate. Chloride appears to cis-inhibit sulfate uptake and to trans-stimulate sulfate efflux. Cis-inhibition and trans-stimulation studies with a variety of anions indicate that this exchange system may be shared by HCO/sub 3//sup -/, S/sub 2/O/sub 3//sup 2 -/, SeO/sub 4//sup 2 -/, and MoO/sub 4//sup 2 -/ but not by H/sub 2/PO/sub 4//sup -/ or HAsO/sub 4//sup 2/. Studies indicate that protons may play two distinct roles in sulfate transport in this system. These studies show that the carrier-mediated system can function in the absence of chloride. The overshoot observed in the presence of a proton gradient indicates that under those conditions the mechanism of transport may be a SO/sub 4//sup 2 -/-OH/sup -/ exchange.
- Research Organization:
- Univ. of Alabama, Birmingham (USA)
- OSTI ID:
- 6804931
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 253:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MEMBRANE TRANSPORT
BIOCHEMICAL REACTION KINETICS
RESPIRATORY TRACT CELLS
TRANSMISSION ELECTRON MICROSCOPY
SULFUR 35
UPTAKE
ALKALINE PHOSPHATASE
ATP-ASE
DOSE-RESPONSE RELATIONSHIPS
ENZYME ACTIVITY
EPITHELIUM
SULFATES
TRACHEA
ACID ANHYDRASES
ANIMAL CELLS
ANIMAL TISSUES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
ELECTRON MICROSCOPY
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
HYDROLASES
ISOTOPES
KINETICS
LIGHT NUCLEI
MICROSCOPY
NUCLEI
OXYGEN COMPOUNDS
PHOSPHATASES
PHOSPHOHYDROLASES
RADIOISOTOPES
REACTION KINETICS
RESPIRATORY SYSTEM
SULFUR COMPOUNDS
SULFUR ISOTOPES
TISSUES
550201* - Biochemistry- Tracer Techniques