This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Protein targeted for destruction in eukaryotes are covalently linked to \nSelect and explain. \nA. Clathrin, B. Pepsin, C. Laminin, D. Ubiquitin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ubiquitin plays a major role in the degradation of proteins and is particularly associated with the disposal of misfolded proteins.\nIt is a small, highly conserved protein that plays a key role in marking various proteins for subsequent degradation in proteosomes.', 'role': 'assistant'}]