Petr Kuzmic wrote:
>Herbert M Sauro wrote:
[...]
>>But as a scientist one needs to understand
>> what's going on inside and for that one needs some sort of organising
>> framework, and for me that turned out to be MCA/MCT.
>[...]
>[...]
>I'd like to contrast what
>Herbert wrote with the following statement, taken from Athel's FAQ page:
>>"Metabolic control analysis tends to treat the kinetic properties of the
>component enzymes as a black box. Some authors have been very critical
>of this, suggesting that shedding light on mechanism is the only reason
>for studying kinetics in the first place. [...] Studies of biochemical
>kinetics have been dominated for nearly a century by an interest in
>molecular mechanisms, but for understanding how whole pathways behave it
>has been found useful to decrease the emphasis on mechanism. [...]"
>>Am I missing something?
Without trying to be facetious, I think you're missing the bits you replace
with "[...]", i.e. the bits that explain that at every level of
understanding there are things that count as fine details for one purpose
and as the whole point for others
(http://ir2lcb.cnrs-mrs.fr/~athel/mcafaq.htm#whyignore). If I say "I'd like
to understand what's going on inside the White House" it's likely that I
want understanding at a coarser level than in terms of chemical reactions.
Metabolic control analysis wants to know what the various enzymes are
doing, but not how they are doing it (which is a perfectly legitimate, but
separate, area of enquiry). Returning to David Garfinkel, therefore, I
think that in some of his investigations he made it unnecessarily difficult
and complicated by concentrating on the mechanisms of the individual
enzyme-catalysed reactions when it would have given the same information in
a more understandable form if he had used rate equations for the complete
reactions. I think that somewhere he showed that this was legitimate but
then continued with detailed mechanisms regardless.
athel
Athel Cornish-Bowden
athel at ibsm.cnrs-mrs.fr
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