K/sup +/-pNPPase located at the gastric epithelial cell exterior accounts for half of the total K/sup +/-pNPPase associated with Na/sup +/, K/sup +/-ATPase

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7189773

Nandi, J; Levine, R A; Das, P K; Ray, T K

Highly enriched and viable surface epithelial cells (SEC) isolated from rabbit stomach were used to study the ouabain-sensitive Na/sup +/, K/sup +/-ATPase and K/sup +/-pNPPase activities before and after lysis of the intact SEC. The viability of the SEC was monitored by erythrosin B dye exclusion. The function of the Na/sup +/, K/sup +/-ATPase pump was evaluated by measuring the ouabain-sensitive /sup 86/Rb/sup +/ uptake, which reached a steady-state (40-50 nmoles/10/sup 6/ cells) within 15-20 min at 37/sup 0/C and maintained such a level for 60 min. Absence of any ouabain-insensitive H/sup +/, K/sup +/-ATPase activity in the lysed cells ensured negligible contamination from parietal cells. The intact SEC showed no Na/sup +/, K/sup +/-ATPase and insignificant Mg/sup +2/-ATPase activity. However, a significant K/sup +/-pNPPase (0.93 +/- .034 ..mu..moles/h.10/sup 6/ cells) responsive to oubain inhibition was demonstrated by localizing its activity to the cell surface exterior. The lysed SEC, on the other hand, demonstrated both the ouabain-sensitive Na/sup +/, K/sup +/-ATPase and K/sup +/-pNPPase activities and were 1.14 and 1.84 ..mu..moles/h.10/sup 6/ cells, respectively. The data demonstrated the ATP hydrolytic site of the Na/sup +/ K/sup +/ATPase to be facing the cytosol while the associated K/sup +/-pNPPase to be distributed equally across both sides of the plasma membrane. The data are consistent with a recent model of the monovalent cation transporting ATPase systems reported in gastric microsomes.

• Research Organization: State Univ. of New York Upstate Medical Center, Syracuse
• OSTI ID: 7189773
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATIONS
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
ENZYME ACTIVITY
ENZYMES
EPITHELIUM
GASTROINTESTINAL TRACT
GLYCOSIDES
HYDROLASES
INHIBITION
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LYSIS
MAGNESIUM COMPOUNDS
MAMMALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OUABAIN
PHOSPHOHYDROLASES
POTASSIUM COMPOUNDS
RABBITS
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM COMPOUNDS
STOMACH
STROPHANTHINS
TISSUES
TRACER TECHNIQUES
VERTEBRATES
VIABILITY