From owner-metabolic-reg@net.bio.net Tue Jan 11 22:00:00 1994
Newsgroups: bionet.metabolic-reg
Path: biosci!daresbury!doc.ic.ac.uk!uknet!pipex!uunet!utcsri!helios.physics.utoronto.ca!alchemy.chem.utoronto.ca!mroussel
From: mroussel@alchemy.chem.utoronto.ca (Marc Roussel)
Subject: Re: sources on various Keq values?
Message-ID: <1994Jan12.015516.4188@alchemy.chem.utoronto.ca>
Date: Wed, 12 Jan 1994 01:55:16 GMT
Distribution: bionet
References: <2gupe4$idp@mserv1.dl.ac.uk>
Organization: Department of Chemistry, University of Toronto
Lines: 17

In article <2gupe4$idp@mserv1.dl.ac.uk> "" <unknown@dl.ac.uk> writes:
>A single enzyme is capable of taking a reaction essentially to completion,
>far from thermodynamic equilibrium.

This is only possible if there is a reactant flux.  A closed chemical
system (with or without enzyme) will always relax to a state of
thermodynamic equilibrium.  Enzymes cannot alter the equilibrium state.

>And if this is true, how applicable is the thermodynamic
>equil. constant to computing the relative levels of the compunds *in vivo*?

     Many in vivo processes operate very far from equilibrium (living
organisms necessarily being open systems) so that equilibrium constants
are essentially useless for the purpose of determining in vivo concentrations.

				Marc R. Roussel
                                mroussel@alchemy.chem.utoronto.ca

.