Final answer:
Protein maturation involves processes such as proteolytic cleavage, formation of quaternary structures, chemical modifications, and correct folding. Methylation is not involved in protein maturation.
Step-by-step explanation:
Protein maturation may involve several processes, including proteolytic cleavage, formation of quaternary structures, chemical modifications, and correct folding. However, it does NOT involve methylation. Methylation refers to the addition of a methyl group to a molecule, typically DNA or RNA, and is not directly involved in protein maturation.