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), Journal Name: Plant Physiol., Suppl.; (United States) Vol. 83:4; ISSN PPYSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
CARBOXYLIC ACID SALTS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENDOPLASMIC RETICULUM
ENZYMES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
IONS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MEMBRANE TRANSPORT
MEMBRANES
METALS
NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
OXALATES
OXIDOREDUCTASES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SEPARATION PROCESSES
TRACER TECHNIQUES