Leucine/Isoleucine

[amaryl]

Dear all,

How does the mass spectra of leucine and isoleucine appears to be when analyzing the proteins/peptides fragments (MALDI-TOF/ESI-TOF).

They both have same molecular weight/mass (m/z is same). how is the resolution obtained in case of isomeric amino acids or they usually overlap?

Hope my query is clear.


Thanks in advance.

Regards,

Amaryl.

[amaryl]

Dear all,

I have no hand on experience with LC/MS though i have with HPLC-UV.

If someone could highlight the problems that usally occur during analysis of proteins by LC/MS (getting the sequence of amino acids)?

Is getting separation of isomeric amino acids a headache by LC/MS?

Your help would be highly appreciated.

Thanks and Regards,

Amaryl.

[Noser222]

Are you doing reverse-phase analysis of peptide fragments and trying to separate individual amino acids? I don't know if that is possible by reverse-phase without derivitizing them, but my experience is limited. I've used the Phenomenex EZ:Faast kit for amino acids and it resolves leucine and isoleucine.