What is citrullination?

What is citrullination?

• A. Deamination of arginine to citrulline
• B. Oxidation of arginine
• C. Phosphorylation of arginine
• D. Conversion of arginine to citrulline

Answer: (D)

Citrullination is a post-translational modification in which the arginine residue in a protein is enzymatically converted to citrulline by peptidylarginine deiminases. This reaction changes the guanidino group of arginine into a ureido group, resulting in loss of positive charge at physiological pH and altering protein structure and interactions. The best description here is the conversion of arginine to citrulline, because it captures the exact chemical transformation that defines citrullination. The other ideas describe different types of changes (oxidation, phosphorylation) or use an imprecise term; citrullination specifically refers to the conversion of arginine into citrulline.

Citrullination is a post-translational modification in which the arginine residue in a protein is enzymatically converted to citrulline by peptidylarginine deiminases. This reaction changes the guanidino group of arginine into a ureido group, resulting in loss of positive charge at physiological pH and altering protein structure and interactions. The best description here is the conversion of arginine to citrulline, because it captures the exact chemical transformation that defines citrullination. The other ideas describe different types of changes (oxidation, phosphorylation) or use an imprecise term; citrullination specifically refers to the conversion of arginine into citrulline.