David Fell <daf at brookes.ac.uk> wrote in message
news:4.3.2.7.0.20000818142954.00b05290 at csmail.brookes.ac.uk...
> I'm sorry I was away on holiday when this discussion faded out because I
> think it deals with a crucial point that merits continued
> consideration. For a long time I was happy to accept Henrik Kacser's view
> that MCA was an analysis, not a theory. However, I think the point has
> been well made in these discussions that MCA/MCT has axioms that lead of
> necessity to certain conclusions, and that any specific application comes
> from a conjunction of this set of axioms (and their derived consequences)
> and the set of assumptions about (or initial conditions of) a specific
> system. In this sense, it really isn't different from other things that
> are called theories, whether special relativity or the origin of species
by
> natural selection.
>> What would be the advantage of deciding to call it a theory? It would
> focus our minds on a pithy and accurate statement of what the theory is
> about. If we could agree on that, and promote it, it would be more likely
> that we could get it referred to in textbooks. I have no doubt that there
> has been a rival theory of metabolic control - it is the principle of
> control of a pathway by a single rate limiting step, and its corollaries
> that the rate limiting step is a feedback-inhibited enzyme at the
beginning
> of a pathway. MCA cannot just be the theory that says that the theory of
> the necessary existence of rate-limiting steps is wrong.
>> What could be possible contenders for the statements of MCT? I suggest:
> 1. The total amount of control of flux exertable by the enzymes of a
> metabolic pathway is limited. (No need to tie it to the particular value
of 1)
> 2. The control of metabolite concentrations is not so limited.
> 3. The control is potentially distributed over the components of the
> system in a way that depends on all the components of the system and
varies
> with the operating conditions of the pathway.
>> Corollary of 1: large changes of flux are not achieved by control at a
> single enzyme site.
> Corollary of 2 : specific control mechanisms are needed to limit
> concentration changes when fluxes change.
>> I'll be interested in reactions,
>> David
> =========================================================
> David Fell, School of Biological & Molecular Sciences,
> Oxford Brookes University, Oxford OX3 0BP, UK
> Tel. +44 (0)1865 483247 FAX +44 (0)1865 484017
>http://bms-mudshark.brookes.ac.uk/>> Sorry to interrupt your discussion but I'm hoping to find further
information on Metabolic Therapy, and its use with regards to brain
injuries. Apparently certain metabolic compounds have been developed
consisting of amino acids and lipids which can increase conductivity between
cells hence influence speech and movement There was a seminar here in
Australia given by DrA Dotsenko and Dr A Schapov recently but I was unable
to attend, apparently the treatment is used extensively overseas with
favorable results however I haven't been able to find any web sites. Does
anyone have any info/sites on such treatment . Regards, Sandra Hopton
(hopeful mum)
> ---
