For the following 10 questions, consider 5 proteins: Proline, Lysine, Serine, Gl
ID: 1002260 • Letter: F
Question
For the following 10 questions, consider 5 proteins: Proline, Lysine, Serine, Glutamic acid, Phenylalanine. Each is 50 amino acids long, made of just a single type of amino acid.
a) which has the most restricted secondary structure?
b) which has the highest isoelectric point?
c) which has the highest molecular weight?
d) which has the strongest tertiary attractions?
e) which could have H-bonds in its tertiary structure at pH 2 but not pH 13?
f) which would have the highest A280?
g) which is the most soluble in water?
h) which has the weakest quaternary attractions with other same proteins at pH 3?
i) which would have the strongest quaternary interactions at pH 7?
j) which has the strongest quaternary repulsions at pH 3?
Explanation / Answer
a) Proline
b) Pro 6.29 Lys 3.86 Ser 5.68 Glu 4.25 Phe 5.48
c) Phenylalanine
d) Lysine
e) Glutamic acid, pKa=4.25
f) Phenylalanine (amino acids with aromatic rings has major absorbance at 280)
g) glutamic acid (major H bonds)
h) Serina (h-bonds)
i) Serine (H-bonds)
j)Proline (more positive charges)