Chem 1120 Quiz 6 Key

 

  1. (12 pts, 3 pts each)
    1. val-gly-leu
    2. arg-lys-his
    3. try-pro-ser
    4. glu-asp-phe

  2. (9 pts, 3 pts each)
    1. The pairs pro-leu and ile-val show hydrophobic interactions because all four amino acids are nonpolar; try-phe are also capable of hydrophobic interactions
    2. Arg-asp and his-glu are both charged and therefore capable of ionic interactions
    3. Thr-glu form hydrogen bonds

  3. (4 pts) We assume that if there are 8 amino acid residues in the octapeptide then there are 8! (40,320) different possible configurations of the amino acids. Given the fragments, we deduce the octapeptide sequence must be phe-glu-phe-asp-his-tyr-glu-his.