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Enzyme
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Query: EC:3.6.3.1 (
Mg2+-ATPase
)
1,484
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effect of
regucalcin
, a calcium-binding protein isolated from rat liver cytosol, on Ca2+-adenosine triphosphatase (ATPase) activity in hepatic microsomes was investigated.
Mg2+-ATPase
activity was clearly increased by the presence of 50 microM Ca2+.
Regucalcin
(1.0-4.0 microM) caused a remarkable elevation (about 3-fold) of Ca2+-ATPase activity. Also,
Mg2+-ATPase
activity was increased (about 1.6-fold) by the presence of
regucalcin
(2.0 and 4.0 microM). Guanosine-5'-O-(3-thiotriphosphate) (GTPrs; 10(-5) and 10(-4) M) and nicotinamide adenine dinucleotide phosphate oxidized form (NADP+; 10(-5) to 10(-3) M) or reduced form (NADPH; 10(-4) and 10(-3) M) significantly increased Ca2+-ATPase activity. These increases were not enhanced by the presence of
regucalcin
(2.0 microM). Of various metal ions, a comparatively low concentration of V5+ (10(-5) M) or Cd2+ (10(-6) M) significantly increased Ca2+-ATPase activity, while Hg2+, Zn2+, Cu2+ and Mn2+ did not have such an effect.
Regucalcin
(2.0 microM) did not enhance the effect of V5+ and Cd2+ on Ca2+-ATPase activity. The present finding, that
regucalcin
activates hepatic microsomal Ca2+-ATPase, suggests a cell physiological role of
regucalcin
as an activator in the microsomal Ca2+-pump activity. This action of
regucalcin
may not be influenced by other regulators.
...
PMID:Activation of hepatic microsomal Ca2+-adenosine triphosphatase by calcium-binding protein regucalcin. 252 22
The role of
regucalcin
, a regulatory protein in intracellular signaling system, in the regulation of Ca2+-ATPase activity in rat heart mitochondria was investigated. Mitochondrial Ca2+-ATPase activity was significantly increased by increasing concentrations of CaCl2 (2.5-50 microM). An increase in the enzyme activity was saturated at 50 microM CaCl2. The addition of
regucalcin
(10(-11)-10(-8) M) in the enzyme reaction mixture caused a significant increase in Ca2+-ATPase activity in heart mitochondria in the presence of 50 microM CaCl2.
Regucalcin
did not have a significant effect on mitochondrial
Mg2+-ATPase
activity.
Regucalcin
(10(-9) M) did not have a significant effect on Ca2+-ATPase activity in the presence of digitonin (10(-3) or 10(-2) %), which is a solubilization effect on membranous lipids. The effect of
regucalcin
in increasing mitochondrial Ca2+-ATPase activity was not observed in the presence of ruthenium red (10(-7) M) or lanthanum chloride (10(-7) M), which is an inhibitor of Ca2+ uniporter. The effect of
regucalcin
(10(-9) M) in increasing mitochondrial Ca2+-ATPase activity was not significantly enhanced in the presence of calmodulin (5 microg/ml) or dibutyryl cyclic AMP (10(-4) M), which is an intracellular signaling factor that can cause a significant increase in the enzyme activity. Mitochondrial
regucalcin
localization was significantly increased in the heart of
regucalcin
transgenic rats as compared with that of normal rats using Western blot analysis. Ca2+-ATPase activity was significantly increased in the heart mitochondria of
regucalcin
transgenic rats. This study demonstrates that
regucalcin
has an activating effect on Ca2+-ATPase in rat heart mitochondria, suggesting its role in the regulation of heart mitochondrial function.
...
PMID:Regucalcin increases Ca2+-ATPase activity in the heart mitochondria of normal and regucalcin transgenic rats. 1678 69
