SDS-Electrophoresis, Dye color change - (Dec/24/2011 )

Anyone ever heard of this happening:

Ran a gel, gel ran fine, in fact, perfect, until about 1-2 cm from the bottom of the gel, the dye turned yellow, and wouldn't move any further. I assume the sample buffer (BMB) turned yellow due to acidity, but I'm at a loss to figure out exactly what is doing that, and how to stop it?

Gel still transfers just fine, and my proteins wavy up the top anyway (like 250 KD). But it's just a random and bugging me. Anyone come across this before?

it's happened to me and my lab mates before. if you let it run longer (if you can) it should turn back. i think it happens because of a buffer component (from the sample) as it passes the bpb. it may happen because of some decomposed sds. if it doesn't affect your result i wouldn't worry.