blurry bands on SDS-PAGE

Emir ekhatipoREMOVE at
Wed Mar 6 11:57:45 EST 2002

Usual troubleshooting tips for cases like that are check that 1) you don't
have too much salt in your sample, 2) don't overload the well, 3) pH of your
sample is 6.8 as that of the stacking buffer... Could your problem be
related to one or more of the above? Do you use pre-cast gels with expired
date and there is no longer a pH shift between stacking and separating gels?

"Michael Witty" <mw132 at> wrote in message
news:Pine.SGI.4.33.0203061519360.2867729-100000 at
> . . . I think they are caused by residues with pKa's near the pH of the
> running buffer, like Histidine (pKa 6.0) and cysteine (pKa of
> thiol/thiolate (pKa about 9).  What do you think?  Regards, Mike.
> (could it be a matter of solubility and caused by Phe and so on?).

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