5 replies to this topic

[science noob]

How much BSA is enough to0 sufficiently block a membrane?

1%? 5%? 10%?

[GNANA]

5% is enough .....

[lab rat]

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.

[BioMiha]

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

[science noob]

BioMiha, on 14 December 2011 - 10:57 PM, said:

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

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.

[bob1]

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