Transport adenosine triphosphatases: properties and functions.

Stekhoven, Feico S.; Bonting, S.L.

doi:10.1152/physrev.1981.61.1.1

Cited by 433 publications

(59 citation statements)

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“…The main enzyme respon sible for the maintenance of proper gradients of the first two ions is the Na + /K + -ATPase, which moves 3 Na + from inside to outside against 2 K + in the opposite direction, with a concomitant hydrolysis of 1 ATP (for review, see Schuurmans-Stekhoven and Bonting, 1981). Brain appears to contain two molecular forms of the enzyme, of which one may be present primarily in neurons (Sweadner, 1979).…”

Section: How Is the Utilization Of Atp Distributed Among The Various mentioning

confidence: 99%

ATP and Brain Function

Erecińska

Silver

1989

J Cereb Blood Flow Metab

751

400

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The importance of A TP as the main source of chemical energy in living matter and its involve ment in cellular processes has long been recog nized. The primary mechanism whereby higher or ganisms, including humans, generate ATP is through mitochondrial oxidative phosphorylation. For the majority of organs, the main metabolic fuel is glucose, which in the presence of oxygen under goes complete combustion to CO 2 and H 2 0:The free energy (.:lG) liberated in this exergonic re action is partially trapped as ATP in two consecu tive processes: glycolysis (cytosol) and oxidative phosphorylation (mitochondria). The first produces 2 mol of ATP per mol of glucose, and the second 36 mol of ATP per mol of glucose. In the latter case, 6 mol of ATP are contributed from the oxidation of 2 mol of NADH generated in the cytosol during gly colysis and transferred into the mitochondria indi rectly through various "shuttle" systems. (In the a-glycerophosphate shuttle, the yield of ATP per NADH is reduced from 3 to 2 because the relevant mitochondrial dehydrogenase is a flavoprotein linked enzyme). Thus, oxidative phosphorylation yields 17-18 times as much useful energy in the form of ATP as can be obtained from the same amount of glucose by glycolysis alone. It is there fore not surprising that limitation of O 2 supply pro duces very damaging effects on cellular function. The brain is one of the organs that is particularly sensitive to lack of oxygen and in humans at rest is responsible for 20% of total O 2 consumption al though it accounts for only 2% of the body weight. in the function of the CNS? It will become evident from our discussion that only partial an swers to these questions are currently available. However, the search for these solutions involves some of the most exciting areas of contemporary neurochemistry. CONCENTRA nONS OF HIGH ENERGY PHOSPHATE COMPOUNDS IN MAMMALIAN BRAINBrain, like all other organs in the body, contains phosphorylated nucleotides that yield energy upon hydrolysis of their phosphate bond(s); the most im portant of these is the adenine nucleotide ATP. In addition, the CNS, in common with other excitable tissues, possesses another high energy reservoir, the creatine phosphate/creatine (PCr/Cr) system,

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Section: How Is the Utilization Of Atp Distributed Among The Various mentioning

confidence: 99%

ATP and Brain Function

Erecińska

Silver

1989

J Cereb Blood Flow Metab

751

400

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“…Taken together, such experiments suggest that both the pump and the receptor functions are properties of the a-subunit. Quantitative binding studies reveal that the receptor site, the phosphorylation site and the ATP-binding site (Munson, 1981(Munson, , 1983Rempeters & Schoner, 1981;Ponzio et al, 1983;Bobis et al, 1983) are present in a 1:1:1 ratio on the active Na,K-ATPase molecule (Wallick et al, 1979;Robinson & Flashner, 1979;Sweadner & Goldin, 1980;Cantley, 1981;Schuurmans Stekhoven & Bonting, 1981;J0rgensen, 1982) (Stein, 1979;Repke & Dittrich, 1979) or (ii) one permanent-high-affinity ATP binding site and one permanent low-affinity, regulatory, ATP binding site per two associated a-subunits (Robinson, 1980;Fritzsch & Koepsell, 1983) or (iii) only a single a-subunit monomer containing one ATP site with changing affinity during the turnover cycle and one cardiac glycoside receptor site (Kyte, 1981;Moczydlowski & Fortes, 1981;Peters et al, 1981) is a much discussed question. These three possibilities are shown schematically in Fig.…”

Section: Receptor Topographymentioning

confidence: 99%

“…The cell surface Na,K-ATPase is one of the most versatile membrane systems as it combines receptor function, coupled Na+: K+ transport and ATPase activity in a single molecule composed of only two different polypeptide chains (a and P) and lipids (Wallick et al, 1979;Robinson & Flashner, 1979;Sweadner & Goldin, 1980;Cantley, 1981;Schuurmans Stekhoven & Bonting, 1981;J0rgen-sen, 1982), as outlined schematically in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

The receptor function of the Na+, K+-activated adenosine triphosphatase system

Anner¹

1985

Biochemical Journal

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“…Higher concentrations of the drug inhibited the enzyme activity. However, this effect was considered a non-specific interaction of the drug with this ATPase [15]. Other agents such as 30 mM Na ÷ and K ÷, 1 mM ouabain, 20 mM NAN3, 10 mM KCN and 0.1 mM dicyclohexylcarbodiimide had no effect on the high affinity Ca2÷-ATPase.…”

Section: Ca2+-a Tpasementioning

confidence: 99%