Which of the following types of protein modifications is characterized by the covalent attachment 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, which can mark the protein for degradation or alter its activity.

Source

Alberts Molecular Biology of the Cell
Protein Metabolism Molecular Biology Protein Modification Medium MEDICAL Confidence: high