Can proteins with sizes smaller than 60 kda be seen as bands in a 6% gel western - (Nov/04/2011 )

I have a western blot for a 160 kda protein which was carried out using a 6% gel. Now I need to control for loading. I tried tubulin and gapdh but neither bands are present.

Any reasons why?

Are there other controls I can use?

Thanks,

they may have run off the gel.

can you run a gradient gel?

try 8% gel. My proteins are 140 and 160 kDa and it works fine. I usually get beta actin at 8%.

Thanks for your replies,

I have managed by repeating the western blot using 7.5 % gel and a loading control with alpha tubulin. Both WRN (160 kda) and alpha tubulin (70kda) bands are detected.