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KINETIC CHARACTERIZATION OF CALCIUM UPTAKE BY THE RAT LIVER GOLGI APPARATUS
Author(s) -
Rojas Patricio,
Surroca Amarilys,
Orellana Ariel,
Wolff Daniel
Publication year - 2000
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1006/cbir.2000.0496
Subject(s) - endoplasmic reticulum , thapsigargin , serca , golgi apparatus , vesicle , calcium , calmodulin , chemistry , calcium pump , atpase , biophysics , biochemistry , biology , enzyme , membrane , organic chemistry
We carried out a kinetic characterization of the Ca 2+ active transport in the rat liver Golgi Apparatus (GA) membrane. Calcium accumulation by vesicles of a GA enriched fraction was found to be a function of both Ca 2+ and ATP‐Mg concentrations, it was inhibited by 2μ m thapsigargin but not stimulated by 3μ m calmodulin. The kinetic parameter values obtained for the GA Ca 2+ pump were: J max of 3.96nmol/mg min, K m for Ca 2+ of 0.150μ m and two K m 's for ATP of 1.14μ m and 519μ m . These results were almost identical to those obtained for the endoplasmic reticulum (ER) fraction, indicating that the GA Ca 2+ pump is a sarco/endoplasmic reticulum (SERCA) P‐type, analogous—if not identical—to that present in the ER.