BSA concentration for blocking - (Dec/14/2011 )

How much BSA is enough to0 sufficiently block a membrane?

1%? 5%? 10%?

5% is enough .....

You can use 1%, if you block longer with shaking. I once made a mistake making TBS + BSA (0.5%) and didn't even notice until the liter was half gone. The background wasn't significantly different, probably because I blocked overnight at 4C.

I myself have generally had bad results with BSA blocking (high background). We use milk instead.

BioMiha on Thu Dec 15 06:57:04 2011 said:

I found the opposite when doing a particular antibody. BSA blot was sparkling clean whilst milk gave alot of grey spots, smears and background after adding ECL. I think it has something to do with the primary antibody. I was detecting a phospho-protein. Milk was fine with the native form.

BSA is quite expensive so I was wondering if 1% does the job, it'll be good to save up on BSA stocks.

Milk is full of phospho-proteins, so it tends to give dirty blots when used with an anti-phospho-protein antibody.