Cytoplasmic marker contamination for Nuclear extracts - Tubulin alfa or beta? (Aug/23/2010 )

Hello,

I am searching a good protein marker for cytoplasmic contamination in nuclear extracts. I think tubulin is a good one, but I am not sure which one to choose: alpha or beta isoform. Is there any difference using one or another? And What do you think about using GAPDH for this control? Thanks!

I use B-tubulin.

What about beta-actin? I think it may also be suitable for that.

Actin is found in both cytoplasm and nucleus.