Differential effects of inhibitors and detergents on the Ca/sup 2 +/-ATPase and Mg/sup 2 +/-ATPase activities of the plasma membrane of a human oat cell carcinoma
Plasma membranes of human oat cell carcinoma possess Mg/sup 2 +/- and Ca/sup 2 +/-dependent ATPase activities of similar magnitude. These activities exhibit the unusual characteristic of being inactiviated by prolonged incubation of the membrane with 1-2 mM dithiothreitol (DTT). Inactivation by DTT was prevented by lowering the incubation temperature, elevation of the membrane protein concentration, and addition of ATP. Fluorosulfonylbenzoyl adenosine (FSBA), an affinity ATP analog, also inactivates these activities. The Ca/sup 2 +/-ATPase activity appears to be more sensitive to both DTT and FSBA. The Ca/sup 2 +/-ATPase activity is more easily inactivated by Triton X-100, while the Mg/sup 2 +/-ATPase is preferentially activated by digitonin. These differential effects of inhibitors and detergents suggest that the Ca/sup 2 +/-ATPase and Mg/sup 2 +/-ATPase are separate enzymes. Incubation of oat cell carcinoma plasma membrane with (/sup 3/H)FSBA resulted in the labeling of several proteins. A labelled 35,000 dalton protein corresponds to the molecular weight of the oat cell carcinoma plasma membrane Ca/sup 2 +/-ATPase previously purified in this laboratory. The identity of one or more of the other labelled proteins with the Mg/sup 2 +/-ATPase has not been demonstrated, but is presently under investigation.
- Research Organization:
- Univ. of California at San Diego, La Jolla
- OSTI ID:
- 5277133
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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ADENOSINE
BIOLOGICAL EFFECTS
ATP-ASE
ENZYME ACTIVITY
DITHIOLS
PROTEINS
LABELLING
AFFINITY
ATP
BLOOD PLASMA
CALCIUM COMPOUNDS
CARCINOMAS
CELL MEMBRANES
DETERGENTS
ENZYME INHIBITORS
MAGNESIUM COMPOUNDS
MAN
MOLECULAR WEIGHT
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ACID ANHYDRASES
ADDITIVES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BODY FLUIDS
CELL CONSTITUENTS
DISEASES
EMULSIFIERS
ENZYMES
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
MEMBRANES
NEOPLASMS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHOSPHOHYDROLASES
PRIMATES
REAGENTS
RIBOSIDES
SURFACTANTS
THIOLS
VERTEBRATES
WETTING AGENTS
550901* - Pathology- Tracer Techniques