You can use fraction V, which is the relatively cheapest, unless you are analysing for something that occurs in plasma. However, non-fat milkpowder is cheaper and usually more effective. Only exception: milk protein is highly phosphorylated and will cause background with anti-phospho-Tyr or anti-phospho-Ser

Dear Sara Elfarrash ,

I can confirm what Engelbert Buxbaum said, Albumin fraction V usually works very well when you want to block your samples for IF or ICC. That said, I have never tested the milk protein in my case.

I personnaly use the Albumin from Bioshop (Cat: ALB001) if you want to look at the caracteristics.

Hai

I aggree with both (Engelbert Buxbaum & Maxime Teiseira) my suggestion is the pH of the PBS Should be in 7.2-7.4, newely prepared , with BSA (Fraction V), prior to start the experiment all the materials should be in ambient temperature, and also use the appropriate materials.

thank you for your answers, this had been very helpful! Engelbert Buxbaum i agree that skimmed milk does its job very well except if i am looking for phospho component (it still works sometimes in my hands though), but we used it for western blotting. Have you tried using skimmed milk as blocking with immunofluorescence with success?

Yes, IHC works like western, except that you need to block peroxydases present in many tissues to avoid background problems.

I think this item is suitable for your application

sigmaaldrich (A9647)

thank you Ali Fouad !