2-mercaptoethanol and DTT

Kresten kresten at my-deja.com
Thu Jun 3 11:32:59 EST 1999


What you usually find in the litterature, is that DTT is a better
reducing agent and smells better (that is less bad) than 2ME, but is
more expensive.

When comparing the reductive power of the two I suspect that you could
find the same comments as when speaking of the chelate-effect. If you
want to compare:

2 2ME-red  = 2ME-ox + H_2      with
DTT-red    = DTT-ox + H_2

you will either get K's (K_concentration) with different units or K's
(thermodynamic) where the comparison between the two depends on the
chosen standard state. IIRC.

Also you could check out tris-(carboxyethyl)phospine (TCEP) which has
several advantages as a reducing agent:

1. It is a very strong reducing agent. Will even reduce DTT-ox.
2. Doesn't smell - well I haven't smelt anything anyway although I
haven't put my nose to much in the stuff.
3. Will work at a low pH, where spontaneous (air catalysed) reoxidation
will probably be less pronounced
4. Will only react with disulfides meaning that many thiol reagents will
not react, eg. alkyl-halogenides, maleimides, vinyl-pyridines, meaning
that one does not need to use a large surplus of reagent in a -SH
modification. And you can even reduce and modify at the same time.


HTH
Kresten
--
The address kresten at my-dejanews.com is for spambots only. Please mail me
at LysLeuLeu at crc.dk , transforming the pre at -part into my initials.
Kresten Lindorff Larsen, Dept. Yeast Genetics
Carlsberg Laboratory, Denmark


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