casein as a block

[Angelbio]

Hi

does anyone have a foolproof recipe for preparing a casein blocking buffer for ELISA - my old one no longer seems to work:

0.5% casein in PBS, heat to dissolve - still not dissolved!

Using Sigma C5890 casein.

thanks

[Elisadeveloper]

If you are set on using the same product from Sigma, then you may have to increase the pH and then adjust back once it's into solution.

I have used I Block (Tropix/applied biosystems) which goes into solution at 90 degrees as you descripbe and is excellent for many assays, or alternatively use pre-prepared Hammarsten grade casein from pierce.

I suspect the sigma stuff might be of lesser and perhaps variable purity affecting solubility

good luck

[Angelbio]

Thanks

I have since bought in some pre-prepared 1% Casein from Thermo Pierce which works a treat.

[Zagami]

See you
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