In article <5u9nk3$fnn at mserv1.dl.ac.uk>, Danny Kohl
<kohl2 at biodec.wustl.edu> writes
>>I am unaware of "experimental results for numerous pathways" which have
>tried to evaluate sum C super J, sub i. I would appreciate being referred
>to them. In the case of yeast hexokinase and G6PDH, we get a variation for
>sum C super J, sub ei from 0.4 to 0.8 as we change from high to low total
>enzyme concentration (with e1 = e2). We have tried using the same data to
>estimate the transit time and use transit time to evaluate sum C super J,
>sub ei (see Kholodenko et al FEBS Letts 1996, 389: 123-125). But the
>transit time is too fast at 20 C to allow this. We hope to get around to
>trying it at lower temperature.
>I am interested in your results you quote here. In recent years I have
not kept up with the literature so I am unaware of your experimental
work. Could you describe in more detail the system you used, was it open
or closed, in vivo or in vitro. What was the shape of the response in
C^J_i when you varied e1=e2, Linear or etc?
I don't quite understand why your sum is less than one as I believe it
indicates 'futile' cycling in the channel, i.e the channel flux is (See
Sauro, Biosystems, vol 33, 55-67 1994 for details) negative and material
cycles between the channel and free enzyme forms.
Is is possible that in your experiments you missed out a step,
biological or non-biological?
Have you tried the same experiments with LDH and G6PDH?
>>Danny Kohl
>Herbert
--
Herbert M Sauro
email: HSauro at fssc.demon.co.uk
Telephone: 01974 282428
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