dc.creator | MASUI, Douglas C. | |
dc.creator | MANTELATTO, Fernando L. M. | |
dc.creator | MCNAMARA, John C. | |
dc.creator | FURRIEL, Rosa P. M. | |
dc.creator | LEONE, Francisco A. | |
dc.date.accessioned | 2012-10-19T14:15:13Z | |
dc.date.accessioned | 2018-07-04T15:01:59Z | |
dc.date.available | 2012-10-19T14:15:13Z | |
dc.date.available | 2018-07-04T15:01:59Z | |
dc.date.created | 2012-10-19T14:15:13Z | |
dc.date.issued | 2009 | |
dc.identifier | COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY, v.153, n.2, p.141-148, 2009 | |
dc.identifier | 1095-6433 | |
dc.identifier | http://producao.usp.br/handle/BDPI/20874 | |
dc.identifier | 10.1016/j.cbpa.2009.01.020 | |
dc.identifier | http://dx.doi.org/10.1016/j.cbpa.2009.01.020 | |
dc.identifier.uri | http://repositorioslatinoamericanos.uchile.cl/handle/2250/1617653 | |
dc.description.abstract | This investigation provides an extensive characterization of the modulation by ATP, Mg(2+), Na(+), K(+) and NH(4)(+) of a gill microsomal (Na(+),K(+))-ATPase from Callinectes danae acclimated to 15 parts per thousand salinity. Novel findings are the lack of high-affinity ATP-binding sites and a 10-fold increase in enzyme affinity for K(+) modulated by NH4+, discussed regarding NH4+ excretion in benthic marine crabs. The (Na(+),K(+))-ATPase hydrolyzed ATP at a maximum rate of 298.7 +/- 16.7 nmol Pi min(-1) mg(-1) and K(0.5) = 174.2 +/- 9.8 mmol L(-1) obeying cooperative kinetics (n(H) = 1.2). Stimulation by sodium (V = 308.9 +/- 15.7 nmol Pi min(-1) mg(-1), K(0.5) = 7.8 +/- 0.4 mmol L(-1)), magnesium (299.2 +/- 14.1 nmol Pi min(-1) mg(-1), K(0.5) = 767.3 +/- 36.1 mmol L(-1)), potassium (300.6 +/- 153 nmol Pi min(-1) mg(-1), K(0.5) = 1.6 +/- 0.08 mmol L(-1)) and ammonium (V = 345.1 +/- 19.0 nmol Pi min(-1) mg(-1), K(0.5) = 6.0 +/- 0.3 mmol L(-1)) ions showed site-site interactions. Ouabain inhibited (Na(+),K(+))-ATPase activity with K(1) = 45.1 +/- 2.5 mu mol L(-1), although affinity for the inhibitor increased (K(1) = 22.7 +/- 1.1 mu mol L(-1)) in 50 mmol L(-1) NH(4)(+). Inhibition assays using ouabain plus oligomycin or ethacrynic acid suggest mitochondrial F(0)F(1)- and K(+)-ATPase activities, respectively. Ammonium and potassium ions synergistically stimulated specific activity up to 72%, inferring that these ions bind to different sites on the enzyme molecule, each modulating stimulation by the other. (C) 2009 Elsevier Inc. All rights reserved. | |
dc.language | eng | |
dc.publisher | ELSEVIER SCIENCE INC | |
dc.relation | Comparative Biochemistry and Physiology A-molecular & Integrative Physiology | |
dc.rights | Copyright ELSEVIER SCIENCE INC | |
dc.rights | restrictedAccess | |
dc.subject | Acclimation | |
dc.subject | Ammonium excretion | |
dc.subject | Callinectes danae | |
dc.subject | Euryhaline crab | |
dc.subject | (Na(+),K(+))-ATPase | |
dc.subject | Potassium ion | |
dc.title | Na(+), K(+)-ATPase activity in gill microsomes from the blue crab, Callinectes danae, acclimated to low salinity: Novel perspectives on ammonia excretion | |
dc.type | Artículos de revistas | |