Question

Addition of which Amino Acid will increase UV absorption

• A. Tryptophan
• B. Leucine
• C. Proline
• D. Arginine

Answer 1

The Correct Option is A

In biochemistry, the ultraviolet (UV) absorption properties of amino acids are primarily determined by the presence of aromatic rings in their structure. Amino acids like tryptophan, tyrosine, and phenylalanine have aromatic side chains, which allow them to absorb UV light, particularly around the 280 nm wavelength.

Amino Acid Analysis:

• Tryptophan: Contains an indole ring, a type of aromatic ring, making it highly absorbent in the UV spectrum. It is the most significant contributor to UV absorption among amino acids.
• Leucine: A non-polar, aliphatic amino acid with no aromatic ring. It does not significantly absorb UV light.
• Proline: Contains a pyrrolidine ring, but it is non-aromatic, leading to minimal UV absorption.
• Arginine: Polar with a guanidinium group but lacks an aromatic ring, resulting in low UV absorbance.

Given the options, the addition of Tryptophan would most significantly increase UV absorption due to its aromatic indole ring.