Proton-stimulated Cl-HCO/sub 3/ antiport by basolateral membrane vesicles of lobster hepatopancreas

Journal Article · Fri May 01 00:00:00 EDT 1987 · Am. J. Physiol.; (United States)

OSTI ID:6409361

Ahearn, G A; Grover, M L; Tsuji, R T; Clay, L P

Purified epithelial basolateral membrane vesicles were prepared from lobster hepatopancreas by sorbitol gradient centrifugation. Na+-K+-adenosinetriphosphatase, alkaline phosphatase, and cytochrome-c oxidase enzyme activities in the final membrane preparation were enriched 9.6-, 1.4-, and 0.4-fold, respectively, compared with their activities in the original tissue homogenate. Vesicle osmotic reactivity was demonstrated using 60-min equilibrium /sup 36/Cl uptake experiments at a variety of transmembrane osmotic gradients. /sup 36/Cl uptake into vesicles preloaded with HCO/sub 3/ was significantly greater than into vesicles lacking HCO/sub 3/. This exchange process was stimulated by a transmembrane proton gradient (internal pH greater than external pH). Proton-gradient-dependent Cl-HCO/sub 3/ exchange was potential sensitive and stimulated by an electrically negative vesicle interior. /sup 36/Cl influx (4-s exposures) into HCO/sub 3/-loaded vesicles occurred by the combination of 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid sensitive, carrier-mediated transfer and apparent diffusion. /sup 36/Cl influx was a hyperbolic function of both internal (HCO/sub 3/) and internal (Cl). The two internal anions displayed a 100-fold difference in apparent affinity constants with HCO/sub 3/ being strongly preferred. /sup 36/Cl influx was stimulated more by preloaded monovalent than by divalent anions. Na was an inhibitor of proton-dependent anion antiport, whereas K had no effect. A model for HCl-HCO/sub 3/ antiport is suggested that employs combined transmembrane concentration gradients of Cl and HCO/sub 3/ to power anion exchange and transfer protons against a concentration gradient.

• Research Organization: Univ. of Hawaii, Manoa, Honolulu
• OSTI ID: 6409361
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ALKALINE PHOSPHATASE
ENZYME ACTIVITY
ATP-ASE
CHLORIDES
MEMBRANE TRANSPORT
CYTOCHROME OXIDASE
ACID CARBONATES
ANIONS
CELL MEMBRANES
CENTRIFUGATION
CHLORINE 36
ION EXCHANGE
LIVER
LOBSTERS
MATHEMATICAL MODELS
OSMOSIS
PANCREAS
PROTONS
TRACER TECHNIQUES
ACID ANHYDRASES
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHARGED PARTICLES
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
CRUSTACEANS
DECAPODS
DIFFUSION
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
ENDOCRINE GLANDS
ENZYMES
ESTERASES
FERMIONS
GLANDS
HADRONS
HAEM DEHYDROGENASES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
INVERTEBRATES
IONS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MEMBRANES
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANS
OXIDOREDUCTASES
PHOSPHATASES
PHOSPHOHYDROLASES
RADIOISOTOPES
SEPARATION PROCESSES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques