On May 20, 2010, at 1:39 PM, Lijun Liu wrote:
I think this is somehow tortured, especially by a quick reading of
Dale's explanation.
If I understand what you are saying, I think it is too.
You imply that asymmetry in the enzyme results in two isomerase
pathways. This may be true, but it
If I understand what you are saying, I think it is too.
You imply that asymmetry in the enzyme results in two isomerase
pathways. This may be true, but it has no consequence on the
prospects for irreversibility. To avoid confusion, let's call these
pathways D and S. Both the D and S
I think we are having a problem with the definition of reversible
and irreversible. By Lijun's definition the reaction is irreversible
because it proceeds from far from equilibrium toward equilibrium. That
situation is more a property of the system than the enzyme. If you make
the enzyme
Dear, Dale, Lijun, Michael and all,
Thank you all very much for your comment and discussion, from which not only do
I find the answer to my question, but also I have learned a lot.
In my case, both substrates are in the same form, saying 'D'. And I don't
expect extra energy to break the EQ
Interestingly, Maxwell's demon pops up here, wh... ,
don't do it.
If you change the reaction rate in one direction 1000 times slower
than
in the other direction, then the reaction becomes practically
irreversible. And the system might not be at equilibrium.
Maia
R. M. Garavito
You absolutely right, I thought about it.
Maia
Marius Schmidt wrote:
Interestingly, Maxwell's demon pops up here, wh... ,
don't do it.
If you change the reaction rate in one direction 1000 times slower
than
in the other direction, then the reaction becomes practically
Dear Vinson,
I would agree with you on choice B. There are probably many ways to look at
it. Here are two that come to me at the moment.
1. If the reaction is reversible, then there's no opportunity to put energy
into the system to reduce its overall entropy. So a reversible epimerase would
Barring some grammatical errors, you've pretty much summed it up.
James
On May 18, 2010, at 12:31 AM, Vinson LIANG wrote:
Dear all,
Sorry for this silly biochemistory question. Thing is that I have a
reversible epimerase and I want to mutate it into an inreversible
one. However, I
I think that it's possible to do a mutation that affects only one way of
the reaction. You can mutate a residue that makes contacts only with the
product of the direct way or only of the reverse way.
Maia
Randy Read wrote:
Dear Vinson,
I would agree with you on choice B. There are probably
You could make use of product binding energy to drive the
reaction forward while the substrate/product is bound to the
enzyme. But enzymes that pull that trick are barely
enzymes - they stay stuck to the first product they make
until something else uses some energy to release it.
You can't
Hi,
I'm more of a Fourier coefficient kind of guy, but I thought that a
ΔG of zero simply corresponded to an equilibrium constant of one. You
can certainly have reversible reactions with other equilibrium constants.
In fact I think irreversible reactions are simply ones where the
equilibrium
Vinson,
As Dale and Randy pointed out, you cannot change the ΔG of a reaction
by mutation: enzyme, which is a catalyst, affects only the activation
barrier (ΔE double-dagger). You can just make it a better (or
worse) catalyst which would allow the reaction to flow faster (or
slower)
If you change the reaction rate in one direction 1000 times slower than
in the other direction, then the reaction becomes practically
irreversible. And the system might not be at equilibrium.
Maia
R. M. Garavito wrote:
Vinson,
As Dale and Randy pointed out, you cannot change the ΔG of a
Sounds like a good explanation. Thank you.
Maia
Dale Tronrud wrote:
If you change the reaction rate in one direction 1000 times slower then
the reaction rate in the other direction will also be 1000 times slower
and the equilibrium will be in exactly the same place. You can't make
the
Dear all,
Sorry for this silly biochemistory question. Thing is that I have a reversible
epimerase and I want to mutate it into an inreversible one. However, I have
been told that the ΔG of a reversible reaction is zero. Which direction the
reaction goes depends only on the concentration of
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