Question

Of the amino acids listed below, which three amino acids can undergo posttranslational modification?

• A. Glycine, Leucine, Tryptophan
• B. Serine, Threonine, Tyrosine
• C. Cysteine, Glutamine, Proline
• D. Glutamic acid, Arginine, Methionine

Hint:

Amino acids with hydroxyl groups—Serine, Threonine, and Tyrosine—are the primary residues that undergo phosphorylation, a major form of posttranslational modification.

Answer 1

The Correct Option is B

Step 1: Understand posttranslational modification (PTM)
PTMs are chemical changes made to a protein after its translation. One common type is phosphorylation, which plays a crucial role in cell signaling and protein function.

Step 2: Identify amino acids that can be phosphorylated
The hydroxyl (-OH) groups in the side chains of Serine, Threonine, and Tyrosine make them suitable for phosphorylation.

Step 3: Confirm absence of -OH in other options
Other amino acids like Glycine, Leucine, and Tryptophan do not have suitable side chains for phosphorylation-based PTMs. Hence, they are not the correct answer.