a question.....

Michael Dorsett Onken mdonken at artsci.wustl.edu
Fri Oct 2 15:11:02 EST 1998

med.student! (alagor at euroweb.hu) wrote:  : Hi folks,


: But..., the book (and here it mentions something, which wasnt even written
: in the "Molecular Cell Biology" from a group of Harvard and Oxford
: proffessors!),...they mention an antagonsist for the K+, its name being
: Ouabain..., its difficult to understand in what respect it is being an
: antagonist to the ion (and the book definetley refers to Ouabain being the
: antagonist of K+).

: Well, if anybody knows the answer to this mysterious Ouabain, then please
: respond...

Ouabain (wah-bane) is a sterol-glycoside isolated from the African Ouabaio
tree.  Ouabain binds the the potassium site of the Na/K-ATPase with higher
affinity than potassium.  This inhibits the translocation of sodium and
potassium across the membrane such that their gradients are lost and the
cell's ability to polarize/depolarize is lost.  Your book should
(hopefully) have a chapter on enzymes and competitive inhibitors, which
will shed more light on how ouabain, or any other antagonist, works.

Mike Onken        -. .-.   .-. .-.   .  E-mail:
Molecular Cell    ||X|||\ /|||X|||\ /|   mdonken at artsci.wustl.edu
Biology Program   |/ \|||X|||/ \|||X||  URL:
Washington Univ.  '   `-' `-'   `-' `-   http://madsci.wustl.edu/

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