biochem amino acids question

Question

which of the following tripeptides is most hydrophobic:

a) gly-ser-ther

b) gly - val - ala

c)phe-val-iso

d)arg-lys-meth

e)ser-iso-leu

I am leaning more towards B but I want to know the correct answer please!

Answer 1

If you look at the structures of the various amino acids making up the individual tripeptides, and pay special attention to the side chains of those amino acids, you see that in C (phe-val-iso), all of these amino acids have hydrophobic side chains making this tripeptide the most hydrophobic. Options B and E each have 2 amino acids with hydrophobic side chains (val and ala in B and iso and leu in E) and option D has one amino acid with a hydrophobic side chain (meth). These are my reasons for choosing option C.