Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.6.3.1 (
Mg2+-ATPase
)
1,484
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Calmodulin-free ghost membranes were prepared from erythrocytes of
kwashiorkor
children and from healthy children in the same age bracket. In the absence of calmodulin, the specific activity of Mg2+-dependent Ca2+-pumping ATPase (Ca2+ +
Mg2+-ATPase
) of
kwashiorkor
membranes was more than 40 percent lower than the specific activity of the normal enzymes, whose maximum velocity was increased by at least four-fold by the modulator protein. In contrast, the maximum velocity of the enzymes of
kwashiorkor
membranes was enhanced by calmodulin by about 1 1/2 times the basal activity of the normal enzymes and by 2 times the basal activity of the
kwashiorkor
enzymes. The affinity of the pump for ATP was lower in the membranes of
kwashiorkor
children (Km for ATP = 30.6 +/- 2.8 microM ATP) in comparison to normal membranes (Km for ATP = 21.7 +/- 2.0 microM ATP). Similarly, calmodulin-affinity of the enzymes, was lower in
kwashiorkor
membranes than in the normal membranes irrespective of source of calmodulin. Calmodulin from haemolysates of
kwashiorkor
red cells activated the enzymes of normal and
kwashiorkor
membranes to the same degree as calmodulin partially purified from the haemolysate of healthy children. A determination of the dependence of the activity of the pump on calcium in the absence and presence of calmodulin reveals that the affinity of the
kwashiorkor
enzymes for Ca2+ is at least 70 percent lower than that of enzymes of normal membranes. Altogether, these findings suggest that the Ca2+-pumping ATPase of
kwashiorkor
membranes is less functional than the enzymes of healthy erythrocytes.
...
PMID:Erythrocyte membrane (Ca2+ + Mg2+)-ATPase in human protein-energy malnutrition. 255 Jan
