EGTA

[Chong Wai Yin( Zhang Weixian)]

Hi people! Can anyone tell me are there any difference between using EDTA
and EGTA in lysis buffer. Is the function of EGTA the same as EDTA? Thank
you for answering.

Regards
Kelvin Zhang

[Peter]

In article <7ti5qu$7cg$2...@mawar.singnet.com.sg>, "Chong Wai Yin( Zhang
Weixian)" <wyc...@mbox3.singnet.com.sg> wrote:

> Hi people! Can anyone tell me are there any difference between using EDTA
> and EGTA in lysis buffer. Is the function of EGTA the same as EDTA? Thank
> you for answering.

EDTA- chelates only Ca+2
EGTA- Chelates all divalent cations

In a lysis buffer, I use both as an insurance policy.

Peter

[J. Martinez-Irujo]

Peter wrote:

In fact, both are metal chelons and have similar affinity for Ca2+, but
EGTA has 100 000-fold more affinity for Ca+2 than for Mg+2 (it is indeed
possible to remove calcium leaving magnesium free in solution).
Dissociation constants (expressed as pK=-logK) for Ca+2, Mg+2, Ni+2 and
Cu+2 are (respectively)

EDTA: 10.7; 8.7; 18.6; 18,8
EGTA: 10,9; 5,4; 13,6; 17,8

Hope this helps.

---
Juan J Martínez Irujo
Departamento de Bioquimica
Universidad de Navarra
Spain

[M. Johan Broekman]

Peter wrote:
>
> In article <7ti5qu$7cg$2...@mawar.singnet.com.sg>, "Chong Wai Yin( Zhang
> Weixian)" <wyc...@mbox3.singnet.com.sg> wrote:
>
> > Hi people! Can anyone tell me are there any difference between using EDTA
> > and EGTA in lysis buffer. Is the function of EGTA the same as EDTA? Thank
> > you for answering.
>
> EDTA- chelates only Ca+2
> EGTA- Chelates all divalent cations

NOTA BENE:
As pointed out elsewhere in this thread, it really is the other way
around.
-Han

[Mark Dowton]

To be pedantic, both complex divalent ions generally, just with different
binding constants. EGTA complexes Ca++ better than EDTA, but if you only
have a solution with Mg++ and EGTA in it, the EGTA will still complex the
Mg++ (it will leave a small, but larger concentration of Mg++ free in
solution, moreso than an equimolar concentration of EDTA). You can
calculate the free concentration of any divalent ion from the binding
constants. That said, if you want to get rid of Ca++, as others have
noted, you should use EGTA, while Mg++ or Mn++ are better removed with
EDTA.

In article <7ti5qu$7cg$2...@mawar.singnet.com.sg>, "Chong Wai Yin( Zhang
Weixian)" <wyc...@mbox3.singnet.com.sg> wrote:

> Hi people! Can anyone tell me are there any difference between using EDTA
> and EGTA in lysis buffer. Is the function of EGTA the same as EDTA? Thank
> you for answering.
>

> Regards
> Kelvin Zhang

[Peter]

In article <37FD3550...@csi.com>, "M. Johan Broekman"
<hanbr...@csi.com> wrote:

> As pointed out elsewhere in this thread, it really is the other way
> around.

ooooops!!!
Thank goodness I use both :-)

Peter

[Peter]

In article <37FCCEF5...@unav.es>, jjmi...@unav.es (" J.
Martinez-Irujo") wrote:

> In fact, both are metal chelons and have similar affinity for Ca2+, but
> EGTA has 100 000-fold more affinity for Ca+2 than for Mg+2 (it is indeed
> possible to remove calcium leaving magnesium free in solution).
> Dissociation constants (expressed as pK=-logK) for Ca+2, Mg+2, Ni+2 and
> Cu+2 are (respectively)
>
> EDTA: 10.7; 8.7; 18.6; 18,8
> EGTA: 10,9; 5,4; 13,6; 17,8

What about Zn+2?

For some reason, I seem to recall that EDTA is also capable of chelating Zn+2.

regards,
Peter Pediaditakis

[J. Martinez-Irujo]

Peter wrote:

Both molecules strongly chelate Zn2+, EDTA (pK=16.5) and EGTA
(pK=14.5), as well as several other cations (Cd+2, Fe2+, Fe+3, Mn+2,
Hg+2...). The selectivity toward these cations can be exploited, for
example, removing traces of Ni+2, Co+2 or Zn+2 from soluble His-tagged
proteins, leaving Mg+2 free in solution.

No experience, however, on their effect on lysis buffers.

--
Juan J. Martinez Irujo

[Enrique Castro]

"Chong Wai Yin( Zhang Weixian)" wrote:
>
> Hi people! Can anyone tell me are there any difference between using EDTA
> and EGTA in lysis buffer. Is the function of EGTA the same as EDTA? Thank
> you for answering.

EDTA binds both Ca2+ and Mg2+. EGTA is a chelator more or less selective
for Ca2+, it will not sequester Mg2+ from your solution.

--
##########################################
Enrique Castro
Dept. Bioquimica,
Fac. Veterinaria, UCM.
Ciudad Universitaria. 28040 Madrid. Spain
Tel: 34-91-394 38 90
Fax: 34-91-394 39 09
e-mail: eca...@eucmax.sim.ucm.es
##########################################

[kkerns...@gmail.com]

On Thursday, October 7, 1999 at 2:00:00 AM UTC-5, Chong Wai Yin( Zhang Weixian) wrote:
> Hi people! Can anyone tell me are there any difference between using EDTA
> and EGTA in lysis buffer. Is the function of EGTA the same as EDTA? Thank
> you for answering.
>

> Regards
> Kelvin Zhang

Anyone know of a chelator that can bind Ca2+ without binding Zn2+ as well? I can't find any in most charts.

[Hiranya Roychowdhury]

Depends on your chelation needs.

EGTA is preferred if you do not want to reduce Mg++ activity.


Hiranya S. Roychowdhury, Ph.D.
Professor
Department of Science
Division of Science, Engineering and Math
NMSU-Dona Ana Community College
575 527 7725 (office)

Co-Chair, NMSU Faculty Grievance Review Board

Curriculum & Instruction Committee
Human Anatomy and Physiology Society<http://www.hapsweb.org/>
[http://www.hapsweb.org/graphics/header.jpg]
________________________________
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Sent: Monday, October 8, 2018 1:20:03 PM
To: met...@magpie.bio.indiana.edu
Subject: Re: EGTA

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[WS]

Fluoride might do the trick, if your zinc concentration is not too high.