Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. We have developed a procedure for preparing resealed red cell ghosts that contain ADP but very little ATP. 2. The procedure involves (i) lysis of the cells in a very large volume of lysing solution, (ii) resuspension of the ghosts in a small volume, (iii) the incorporation into the ghosts, before they are resealed, of the adenylate kinase inhibitor P1,P5-di(adenosine-5'-)pentaphosphate (AP5A) and of hexokinase, and (iv) the removal of traces of ATP, formed by residual adenylate kinase activity, by the addition of glucose. 3. Measurements of sodium efflux from ghosts prepared in this way show that sodium-sodium exchange through the sodium pump does not occur in the absence of ATP even if ADP is present. 4. The beta:gamma imido analogue of ATP (AMP.PNP), which is incapable of phosphorylating sodium, potassium-ATPase, cannot replace ATP in supporting sodium-sodium exchange. 5. These findings support the hypothesis that the outward movement of sodium ions through the sodium pump is associated with the transfer of a phosphoryl group from ATP to the enzyme, and that the inward movement of sodium ions through the pump is associated with the return of a phosphoryl group from the phosphoenzyme to ADP.
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PMID:Sodium-sodium exchange through the sodium pump: the roles of ATP and ADP. 53 26

The role of metabolic energy in cell maturation-associated loss of membrane functions has been studied using sheep reticulocytes incubated in vitro at 37 degrees C for periods up to 41 hours. ATP either was maintained with glucose, adenosine plus inosine or depleted with 2-deoxyglucose plus arsenate. Two membrane transport systems were studied: Na+-dependent glycine transport and the sodium pump, estimated from the number of specific [3H] ouabain binding sites per cell. Although both transport systems decreased during maturation, the decrease was much less in ATP-depleted cells compared to ATP-replete cells. The phenomenon is relatively specific: not all maturation-associated changes are similarly affected. Thus, the decreases in activity of the cytoplasmic enzymes glucose-6-phosphate dehydrogenase, hexokinase and phosphoglucose isomerase were not prevented by energy depletion. It is concluded that the loss of certain functions during reticulocyte maturation is retarded by metabolic depletion.
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PMID:The role of metabolic energy in the maturation-associated loss of reticulocyte membrane transport. 650 12