No targeted band - (Aug/05/2008 )

Hi, I'm new to Western Blotting, and am having an issue.

I am blotting for 3 different proteins, each on a different membrane, using the same samples. The proteins have similar masses (60, 57, and 56kDa). I have run samples and blotted twice, but ended up with the same result both times: all samples for all 3 proteins have a band at 30kDa and 13kDa, and there are no bands anywhere near the target mass. Any suggestions?

have you checked your protein preparation? Is it right for your proteins? you have to prepare membrane or nuclear proteins in other ways than cytosolic ones...