IUBio

The Prion Hypothesis

Ralph Leonhardt leo at neuroinformatik.ruhr-uni-bochum.de
Mon Jan 25 06:45:41 EST 1999


On 20 Jan 1999, Sturla Molden wrote:

> In my opinion the prion theory is in violation of the 2nd law of
> thermodynamics. According to the theory, prions grows like
> salt crystals.

Where did you get that from? As far as I know the prion proteins are built
by the bodycells and in the case of disease undergo a change in their
tertiary structure (3D configuration) which is triggered by abnormal
(mutant?) prion proteins and which they themselves are able to pass on to
others.
Similar mechanisms of conformation changes are accepted concerning heat
shock proteins and so-called chaperonins, which are proteins that help
others to reach their correct (biologically active) conformation. I don't
see what this has to do with crystal growth.

<snip>

> In the prion case, however, the entropy of the proteins decreases 
> spontaneously but this is not accompanied by a parallel 
> entropy increase (e.g. from water evaporation). Consequently, 
> the theory must be false. That's my opinion.
> 
> 
> Sturla Molden

I don't think that in the conformation changes there must be a decrease
in entropy involved, since while there are some new bonds made others can
be loosened, so there is no loss in entropy. (I'm no biophysics or
thermodynamics expert, but I don't think, that the prion hypothesis is in
conflict with the 2nd law. The Nobel Committee would have found out!) 

All the best, Leo

-------------------------------------------------------------------------------
Ralph Leonhardt (Dipl.-Biol.)			Tel.:	+49 (0)234 700 5559
Inst. f. Neuroinformatik, Geb. ND 04/297	Fax:	+49 (0)234 709 4209
Ruhr-Universitaet-Bochum
D-44780 Bochum, Germany

E-mail: ralph.leonhardt at neuroinformatik.ruhr-uni-bochum.de
URL:    http://www.neuroinformatik.ruhr-uni-bochum.de/ini/PEOPLE/leo/top.html






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