this phenomenon is usually observed when your buffer contains DTT, EDTA (EGTA)
or other reducing agents and is due to formation of thiol reduction complexes.
L-histidine might also serve as an electron donator.
> Dear all
>> I have just begun using the Talon resin from clontech to purify my his
> tagged protein. On the first run I used 200 mM L-histidine to elute
> from the column. The column turned brown and then this colur eluted
> form the column leaving the column clear not pink as is usual with
> this column resin. Obviously the metal has leached from the column.
> Is this normal when using histidine to elute from heavy metal affinity
> columns? Is there a buffer system to use to avoid this?
>R.Seymour at prospect.anprod.csiro.au>
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