Calmodulin stimulation of calcium transport in carrot microsomal vesicles. [Daucus carota]
ATP-dependent /sup 45/Ca/sup 2 +/ uptake into microsomal vesicles isolated from cultured carrot cells (Daucus carota Danvers) was stimulated 2-3 fold by 5 ug/ml calmodulin (CaM). Microsomal vesicles separated with a linear sucrose gradient showed two peaks with CaM-stimulated Ca/sup 2 +/ uptake activities. One peak (at 1.12 g/cc) comigrated with the activity of the antimycin A-insensitive NADH-dependent cytochrome c reductase. This transport activity was enhanced 10-20 fold by 10 mM oxalate and appeared to be associates with vesicles derived primarily from the ER. The other peak of CaM-stimulated Ca/sup 2 +/ uptake (at 1.17 g/cc) was not affected by oxalate. These vesicles are probably derived from the plasma membrane. Preliminary experiments with the low-density vesicles (ER) vesicles, indicate that inositol-1,4,5-trisphosphate caused a transient reduction in intravesicular Ca/sup 2 +/. These results are consistent with the ER being an important site of intracellular Ca/sup 2 +/ regulation.
- Research Organization:
- Univ. of Maryland, College Park
- OSTI ID:
- 5653383
- Report Number(s):
- CONF-8707108-
- Journal Information:
- Plant Physiol., Suppl.; (United States), Vol. 83:4; Conference: Annual meeting of the American Society of Plant Physiologists, St. Louis, MO, USA, 19 Jul 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM
MEMBRANE TRANSPORT
ENDOPLASMIC RETICULUM
BIOCHEMICAL REACTION KINETICS
CALCIUM 45
CATIONS
CELL MEMBRANES
CHROMATOGRAPHY
OXALATES
OXIDOREDUCTASES
PROTEINS
TRACER TECHNIQUES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOXYLIC ACID SALTS
CELL CONSTITUENTS
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYMES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
IONS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MEMBRANES
METALS
NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
RADIOISOTOPES
REACTION KINETICS
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques