Which Statement About Aromatic Amino Acids is CORRECT

Question

Which statement about aromatic amino acids is CORRECT?
A) All are strongly hydrophilic.
B) Histidine's ring structure results in its being categorized as aromatic or basic, depending on pH.
C) On a molar basis, tryptophan absorbs more ultraviolet light than tyrosine.
D) The major contribution to the characteristic absorption of light at 280 nm by proteins is the phenylalanine R group.
E) The presence of a ring structure in its R group determines whether or not an amino acid is aromatic.

Accepted Answer

On a molar basis, tryptophan absorbs more ultraviolet light than tyrosine. This is because tryptophan has a higher molar extinction coefficient (ε) at 280 nm compared to tyrosine due to its indole ring structure, which results in greater absorbance of ultraviolet light.