Paul Schlosser wrote:
"If I can build a simulation model and put in everything I know about
the enzyme kinetics, over large concentration ranges, then any
subsequent matrix approach will, at best, extract only a subset of the
information in the model. So why settle for a subset?"
This is a woods-and-the-trees question. If you ever heard Henrik Kacser
lecture around 15 years ago or so, you will have heard him say something
along the following lines (in one of those talks with the awful slides
made by taking bad photographs of a Boehringer metabolic pathways
chart): whichever bit of metabolism you study it is just a subset of the
whole, so you will want to fill in the bits around the edges; when you
have done that, you will have new edges and will want to fill in the
bits around them... Eventually your model of a rat will be a complete
rat, and it will behave in every experiment exactly as a real rat would
behave, because it *is* a real rat. In one sense it's the best model you
could possibly have. However, if that's the sort of model you want is is
available in abundance, and has been since long before computers and
matrix algebra were invented. By simplifying the model ("settling for a
subset") we lose detail but we gain in capacity to understand what's
going on.
I think that's essentially the argument (but if anyone remembers it
better than I do please correct me), and I think it's right (however
much I may have disliked the slides Henrik used to illustrate it with).
But one can go further, and I think this is also implicit in Henrik's
earlier papers. Starting around 1965, and continuing over a quarter of a
century, David Garfinkel and his group did a great deal of work
modelling all sorts of things in great detail, but I have the impression
that very little of lasting value has survived: why not? Fashion? or
because it is very difficult to see the wood for the trees (i.e. to
understand what's going on) in a highly detailed model that lacks any
kind of simplifying assumption?
Athel
Home page: http://ir2lcb.cnrs-mrs.fr/lcbpage/athel/home_page.html
MCA FAQ: http://ir2lcb.cnrs-mrs.fr/lcbpage/athel/mcafaq.html
MCA chapter from my book:
http://ir2lcb.cnrs-mrs.fr/lcbpage/athel/fek10/mcai.html
