Effect of palytoxin on the sodium-potassium pump: model and simulation.
We propose a reaction model for the palytoxin-sodium-potassium (PTX-Na(+)/K(+)) pump complex. The model, which is similar to the Albers-Post model for Na(+)/K(+)-ATPase, is used to elucidate the effect of PTX on Na(+)/K(+)-ATPase during the enzyme interactions with Na(+) and/or K(+) ions. Conformational substates and reactions for the pump are incorporated into the Albers-Post model to represent enzymes with or without bound PTX. A mathematical model based on the reaction scheme is used in simulations modeling experimental studies of PTX-induced ionic currents. Our simulations suggest that (i) extracellular Na(+) as well as K(+) promotes PTX-induced channel blockage; (ii) extracellular K(+) accelerates PTX unbinding; and (iii) K(+) occlusion in the PTX-pump complex is essential for describing the PTX-induced current dynamics.
Rodrigues
Antônio M
AM
Biomedical Engineering Program, COPPE, Federal University of Rio de Janeiro, Brazil.
Almeida
Antônio-Carlos G
AC
Infantosi
Antonio F C
AF
D000178:Acrylamides / Q000494:pharmacology*; D000465:Algorithms; D002412:Cations; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D003064:Cnidarian Venoms; D003198:Computer Simulation; D017136:Ion Transport / Q000187:drug effects* / Q000502:physiology; D008954:Models, Biological; D011188:Potassium / Q000737:chemistry / Q000378:metabolism; D012964:Sodium / Q000737:chemistry / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects* / Q000378:metabolism*; D000095702:Polyether Toxins
D000178:Acrylamides; D002412:Cations; D003064:Cnidarian Venoms; D011188:Potassium; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; C010272:palytoxin; D000095702:Polyether Toxins