A soluble protein activator of (Mg2+ + Ca2+)-dependent ATPase in human red cell membranes
| Autor: | D.L. Clough, G.H. Bond |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
Erythrocytes
Hot Temperature Cations Divalent ATPase Biophysics Binding Competitive Hemolysis Biochemistry Hemoglobins chemistry.chemical_compound medicine Animals Humans Magnesium Trypsin Bovine serum albumin Adenosine Triphosphatases chemistry.chemical_classification biology Activator (genetics) Cell Membrane Sodium Serum Albumin Bovine Blood Proteins Cell Biology Enzyme Activation Kinetics EGTA Membrane Enzyme chemistry Ethylmaleimide Potassium biology.protein Plasma membrane Ca2+ ATPase Calcium Cattle Protein Binding medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 323:592-599 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(73)90167-3 |
| Popis: | 1. 1. (Mg2+ + Ca2+)-dependent ATPase in human red cell membranes was stimulated about 2-fold by a soluble activator (or activators) in exhaustively dialyzed, membrane-free hemolysates. 2. 2. The Mg2+-dependent ATPase and (Mg2+ + Ca2+)-dependent ATPase activities in the membranes were unaffected by the hemolysate. 3. 3. Activation of (Mg2+ + Ca2+)-dependent ATPase by hemolysate obeyed Michaelis-Menten kinetics, indicating that the activator binds to saturable sites on the enzyme.The activator increased the maximum velocity ( V ) of the enzyme. 4. 4. When membranes were exposed to N- ethylmaleimide or the heat, (Mg2+ + Ca2+)-dependent ATPase and the hemolysate-dependent component of this activity were inactivated at the same rate, indicating that there is a single (Mg2+ + Ca2+)-dependent ATPase in the membrane which is activated by hemolysate. 5. 5. Evidence that the activator is a protein is based on the following observations: (a) it is non-dialyzable, (b) it is destroyed by trypsin, and (c) it appears to be heat labile. 6. 6. Human hemoglobin and bovine albumin produced a small activation of the enzyme, but it appears that the activator in hemolysate is probably a protein other than hemoglobin. |
| Databáze: | OpenAIRE |
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