Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence has been recently presented of a relative deficiency of Ca2+ - dependent adenosine triphosphatase activity of erythrocyte membranes obtained from patients with hereditary spherocytosis. We have sought to confirm these findings by measuring calcium efflux from intact erythrocytes of patients with hereditary spherocytosis, as well as erythrocyte calcium concentrations, but find both these parameters to be normal. Ca2+-dependent adenosine triphosphatase activity, as well as Ca2+ -dependent membrane phosphorylation was also not found to be deficient in erythrocyte membranes from subjects with hereditary spherocytosis. These studies do not support the postulate that an accumulation of calcium affects the deformability of erythrocytes and their subsequent destruction in the spleen.
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PMID:Studies on calcium transport and calcium-dependent adenosine triphosphatase activity of erythrocyte membranes in hereditary spherocytosis. 13 67

Hereditary spherocytosis (HS) is a congenital haemolytic anaemia which is characterized by a great variety of structural defects in the red cell's membrane skeleton and/or deficiencies in particular membrane (skeletal) proteins. Enhanced (Mg2+)-dependent adenosine triphosphatase (Mg(2+)-ATPase) activities, varying from 115% to 160%, were invariably found in erythrocyte ghosts derived from 13 HS patients. Similarly, an enhancement of Mg(2+)-ATPase activity by 30% is observed in normal red cell ghosts that have been stripped of the greater part of their membrane skeletal proteins by treatment with a low ionic strength buffer. Reassociation of those stripped ghosts with spectrin reduces the enhanced Mg(2+)-ATPase activity to its original level. Since in both cases, HS ghosts and stripped normal ghosts, the stabilizing effects that the membrane skeleton exerts on the maintenance of an endofacial localization of the aminophospholipids are impaired, the enhanced Mg(2+)-ATPase activity is interpreted to reflect an increased activity of the aminophospholipid translocase. The present observations therefore support a role of the membrane skeleton in the stabilization of phospholipid asymmetry in the red cell membrane and consequently in reducing the energy consumption of the translocase.
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PMID:Enhanced Mg(2+)-ATPase activity in ghosts from HS erythrocytes and in normal ghosts stripped of membrane skeletal proteins may reflect enhanced aminophospholipid translocase activity. 778 96