Inhibition of the actions of palytoxin on the K+ efflux from red cells and on the Na/K-ATPase activity by a monoclonal antibody.
Palytoxin (PTX) binds to the Na/K pump, inhibits the (Na/K)-ATPase and forms Na and K permeable channels in human red cells. Here, we report that a monoclonal antibody raised against a derivative of PTX (Bignami, G.S. et al. (1992) Toxicon 30, 687-700) inhibits these effects. The observations are consistent with a model in which (a) the antibody binds and, thus reduces the concentration of free PTX available to react with the Na/K pump, and, (b) the PTX-antibody complex also binds to the PTX receptor on the Na/K pump but in such a way that a cation permeable channel is not formed, probably by reducing the concentration of free PTX. Using this model, we estimate that the apparent dissociation constant for the binding of PTX to antibody is 0.2 nM.
Tosteson
M T
MT
Laboratory for Membrane Transport, Harvard Medical School, Boston, MA 02115.
Bignami
G S
GS
Scriven
D R
DR
Bharadwaj
A K
AK
Tosteson
D C
DC
D000178:Acrylamides; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D000936:Antigen-Antibody Complex / Q000378:metabolism; D003064:Cnidarian Venoms / Q000037:antagonists & inhibitors* / Q000276:immunology; D004789:Enzyme Activation; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000378:metabolism*; D000095702:Polyether Toxins
D000178:Acrylamides; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D003064:Cnidarian Venoms; D007473:Ion Channels; D011188:Potassium; D000254:Sodium-Potassium-Exchanging ATPase; C010272:palytoxin; D000095702:Polyether Toxins