Ok.you are right,actually entropy has contribution as H,of course it seems to me!
On Sun, Oct 24, 2010 at 9:32 PM, <chris.ne...@utoronto.ca> wrote: > Mohsen, > > Writing H as E+PV does not change the nature of my question. It was said > that when computing binding Delta Delta G between two close variants, most > entropic contributions would tend to cancel. My question is why, when there > are many components to the gibbs free energy, would some components (stated > as entropy) cancel in a delta delta G while some are not expected to cancel > (implicitly taken to be enthalpy or internal energy or pressure volume > work). And also, is this a hunch or has it been shown? > > Thanks, > Chris. > > > -- original message -- > > Dear Chris > Do you mean Gibbs free energy? > there are a general relation in statistical mechanics as below: > G=E-TS+PV > in this relation E is internal energy and S is entropy,then enthalepy is > not > comming in relation anywhere, > besides there are not any reason for canceling G when Del Del S is canceled > > On Sun, Oct 24, 2010 at 9:04 PM, <chris.neale at utoronto.ca> wrote: > > Ehud, >> >> when computing binding Delta Delta G between two close variants, why would >> entropy tend to cancel and enthalpy not tend to cancel? Even in the case >> of >> small perturbations, this sounds like wishful thinking to me ;) >> >> Chris. >> >> -- original message -- >> >> Hi Moshen, >> >> I think everybody agrees that a full calculation such as Free Energy >> Perturbation is the accurate, if difficult and lengthy, approach. >> The entropic effects usually cannot simply be ignored. All I tried to >> say was that there are approximation schemes for these (see the >> reference below). Still, I would trust such approximations only when >> computing binding Delta Delta G between two close variants (e.g. a wild >> type protein and a one residue mutation) such that - >> > > > -- > gmx-users mailing list gmx-users@gromacs.org > http://lists.gromacs.org/mailman/listinfo/gmx-users > Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/Search before posting! > Please don't post (un)subscribe requests to the list. Use thewww interface > or send it to gmx-users-requ...@gromacs.org. > Can't post? Read http://www.gromacs.org/Support/Mailing_Lists >
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