The R-group, or side chain, of the amino acid serine is -CH2-OH. The R-group, or side chain, of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Serine and leucine would both be in the interior of the globular protein.
D) Serine and leucine would both be on the exterior of the globular protein.

Question

Quizplus · Accepted Answer

Leucine has a hydrophobic R-group, which would be more likely located in the hydrophobic interior of a globular protein. Serine, on the other hand, has a hydrophilic R-group, which would be more likely located on the hydrophilic exterior of a globular protein. Therefore, leucine would be in the interior and serine would be on the exterior of the globular protein.

The R-Group, or Side Chain, of the Amino Acid Serine