Has anyone seen the white bands on the sds-page after destaining? Even several bands of my pre-stained marker became white after destained. Can anyone explain this phenomenon?
Try to use freshly prepared chemicals... check the ph of the buffers.
coomassie blue is clear/white at pH below 2.0 which may be relevant but how you can achieve this only in the middle of a gel and not at the ends is very hard to explain
I always obtain white streptavidin bands, when I do SDS-PAGE on pulldown elutes from invitrogens dynabeads. The strange colour only affects the STV-band, so I assume it stems from the modification to bind it to the beads. Does not explain the colour change in your marker, though.
I suppose SDS was not properly removed from the sample or the alcohol contetnt of destaining solution is too high or impure SDS.
Wash out SDS with 20% TCA. Only use pure SDS. Reduce methanol or ethanol content of the destaining solution.
Dear Jie:
I have got some bands like the white you have in your gel when working with redox enzymes.
I was looking for an explanation in the literature for a long time. I have also been discussing this phenomenon with some of my co-workers and colleagues. We suspect that some of these redox proteins have their redox centres exposed to their surroundings when they become denatured due to the SDS_PAGE protocol. Redox centres modify somehow the gel colour. I'm pretty sure that this is one of the aspects affecting the colour because we got same effect with pure samples of redox enzymes runned in SDS-PAGE.
This is all I can say,
Have you cut this band to be analysed by Mass spect?
Good luck,
Rosa María
Hello Jie Shen,
We use precast gels and colloidal coomassie blue and also sometimes observed this effect but in our case we saw the white bands after SDS was leached out of the gel prior to staining. It was a mystery to us also but we assumed that the protein was precipitating/aggregating in the gel at its specific location after SDS removal and then was unable to take up stain.
We never discovered whether this was a correct assumption. In your case there is a middle section that seems to be affected but the rest is ok. This is an even deeper mystery as it doesn't seem to happen every time. Is it possible that in this run something has affected the pH in the middle section and caused the proteins to precipitate?
I am sorry I don't have a definitive answer but this is an interesting phenomenon and hopefully someone will know!
check the buffers. Check the strainer. KCl straining gives white colors bands but again only in the middle bands creates confusion.
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