Biomaterial Database

Properties of a membrane-bound phosphatase activity in normal and abnormal red blood cells. 1979

J Delaunay, and S Fischer, and J P Piau, and M Tortolero, and G Schapira

A neutral, membrane-bound, phosphatase activity was characterized in normal red blood cells, using p-nitrophenylphosphate as substrate. Its specific activity was 1.59 nmol mg-1 min-1. The kinetics were of the Michaelis type: KM,app = 2.5 X 10(-3) M. It was stimulated by K+ and inhibited by ouabain, a behaviour reminiscent of (Na+ + K+)-ATPase. In 10 patients with homozygous sickle cell disease and in 11 patients with unidentified congenital hemolytic anemias, the specific activity was significantly increased. In general, the phosphatase retained Michaelis-Menten kinetics. However, in four patients from the same family with an unidentified hemolytic anemia, the kinetics yielded a biphasic curve instead of a rectangular hyperbola, a change consistent with the existence of an inhibition by substrate excess. From detailed analysis of the curve, the apparent inhibitor constant for pNPP was determined: Ki,app approx. 2.5 X 10(-2) M. This novel abnormality of the red cell membrane might be the distinctive feature of a given type of congenital hemolytic anemia.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009597	4-Nitrophenylphosphatase	An enzyme that catalyzes the hydrolysis of nitrophenyl phosphates to nitrophenols. At acid pH it is probably ACID PHOSPHATASE (EC 3.1.3.2); at alkaline pH it is probably ALKALINE PHOSPHATASE (EC 3.1.3.1). EC 3.1.3.41.	4-Nitrophenyl Phosphatase,K+-NPPase,K-Dependent p-Nitrophenylphosphatase,K-p NPPase,Nitrophenyl Phosphatase,p-NPPase,p-Nitrophenylphosphatase,para-Nitrophenyl Phosphatase,para-Nitrophenylphosphatase,4 Nitrophenyl Phosphatase,4 Nitrophenylphosphatase,K Dependent p Nitrophenylphosphatase,K p NPPase,K+ NPPase,p NPPase,p Nitrophenylphosphatase,p-Nitrophenylphosphatase, K-Dependent,para Nitrophenyl Phosphatase,para Nitrophenylphosphatase
D010042	Ouabain	A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.	Acocantherin,G-Strophanthin,Acolongifloroside K,G Strophanthin
D010744	Phosphoric Monoester Hydrolases	A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate.	Phosphatase,Phosphatases,Phosphohydrolase,Phosphohydrolases,Phosphomonoesterase,Phosphomonoesterases,Phosphoric Monoester Hydrolase,Hydrolase, Phosphoric Monoester,Hydrolases, Phosphoric Monoester,Monoester Hydrolase, Phosphoric
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D004910	Erythrocyte Membrane	The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.	Erythrocyte Ghost,Red Cell Cytoskeleton,Red Cell Ghost,Erythrocyte Cytoskeleton,Cytoskeleton, Erythrocyte,Cytoskeleton, Red Cell,Erythrocyte Cytoskeletons,Erythrocyte Ghosts,Erythrocyte Membranes,Ghost, Erythrocyte,Ghost, Red Cell,Membrane, Erythrocyte,Red Cell Cytoskeletons,Red Cell Ghosts
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006720	Homozygote	An individual in which both alleles at a given locus are identical.	Homozygotes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump