Differentiating two proteins? - From the bovine potuitary glands. (Mar/23/2006 )

The two peptides are:

CYS-TYR-PHE-GLN-ASN-CYS-PRO-ARG-GLY(NH2)


and


CYS-TYR-ILE-GLN-ASN-CYS-PRO-LEU-GLY(NH2)

The significant differences between the two is the PHE and ARG in the 1st peptide that is changed with ILE and LEU in the second. ARG is hydrophilic being positively charged, while both ILE and LEU are hydrophobic, and PHE has a ring, and its side chain is also uncharged.

Now the main thing is how do you seperate these? The main things that comes to my mind is ion exchange chromatography, and the gel electrophoresis that seperates based on charges and molecular size (name eludes me atm). A friend of mine also suggested HPLC, though I'm uncertain about this.

So, are these the right methods, and if not, what method should i use? Thanks!

I'm not expert :
I think that reverse phase is used to separate peptides, depending on their hydrophobicity.
First you bind peptide in trifluoracetic buffer, and then you elute with increasing concentration of acetonitrile?

i agree with missele that reverse phase chromatography on hplc will probably work.

isoelectric focusing or chromatofocusing may work.

i think you were thinking of either native page or urea page for charge separations with size component.