Scott:
The prescriptions offered further down in this thread as a CURES, should
be useful answers to your first question.
I'll try to answer you second:
At high voltage gradients, high-molecular weight aggregates (e.g., of
DNA and protein) tend to get driven into under-sized pores, to strech
the gel locally and tighten the pores and clog them (something like the
clogging of a filter). Protein stacked behind these clogged pores gets
deverted around them and contributes to the "streaks"
.
At lower voltage gradients, the aggrgates have more time to disaggregate
and reptate through the less tight pores without clogging them.
If you want to get a better feel of how polyacylamide gel
electrophoresis works, download the Adobe Acrobat version of my original
1964 paper from:
<http://www.pipeline.com/~lenornst/DiscElectrophoresis.html> .
Len Ornstein (of Davis & Ornstein)
Scott McMahan wrote:
>> I was having problems recently with the samples of my Tris-Tricine
> SDS-PAGE/Westerns streaking vertically. After checking the usual suspects
> (old sample buffer, precipitated sample, etc.) I found a few protocol
> books mentioning that turning the current down sometimes helps this
> problem. When I did that, it did drastically decrease the streaking, but
> really increased the running time. I was wondering if anyone knew what
> phenomenon is causing this streaking, and is there some other way of
> correcting it so I can run my gels faster again.
>> --
> Scott McMahan
>mcmahan at oncology.wisc.edu
