Which of the following types of protein modifications involves the addition of a ubiquitin molecule to a lysine residue on the target protein?

A Phosphorylation
B Ubiquitination ✓
C Acetylation
D Glycosylation

Explanation

Ubiquitination is a type of post-translational modification that involves the covalent attachment of a ubiquitin molecule to a lysine residue on the target protein, often marking it for degradation.

Source

Alberts Molecular Biology of the Cell
Protein Metabolism Molecular Biology Protein Modification and Degradation Hard MEDICAL Confidence: high