Your question highly depends on which milk proteins you want to separate. BTW: For many mass-spectrometric methods your protein does not need to be native, it is digested by trypsin anyway.

Thank you for your answer, but the problem, I have to do sequencing some of these proteins (beta-casein, alpha-casein, alpha-lactalbumin and lactoferrin). It is necessary that I send them to the native state.

I also have to do some tests on some of them, so I want them to be native. (Note I work on camel milk). Thank you

I'd suggest a cation exchange column, with some mild detergent in the buffer, because some of those proteins tend to aggregate and even "travel" in faty micelles. 

I would suggest a sequential design, step 1 to purify the higher abundant proteins, and step 2 to purify low abundance proteins from the unbound fractions, if possible.

Hi there,

If you can tell us a bit more about your desired proteins for purification then I can help you.

PM - [email protected]

Whey proteins? LF/LPO or ALAC/BLAC/BSA/Igs?

Cheers

Jagan