Which statement best describes citrullination in the context of anti-CCP?

Which statement best describes citrullination in the context of anti-CCP?

• A. It converts citrulline back to arginine during inflammation.
• B. It causes arginine to citrulline during apoptosis and increases during inflammation.
• C. It affects only enzymes and has no impact on protein shape.
• D. It is not related to cell death processes.

Answer: (B)

Citrullination is a post-translational modification where arginine residues in proteins are converted to citrulline by peptidylarginine deiminases (PADs). This process occurs more during inflammation and in cells undergoing death (like apoptosis), leading to the appearance of new citrullinated epitopes that anti-CCP antibodies recognize. The statement that arginine is converted to citrulline during apoptosis and that this process increases during inflammation matches the biology of how anti-CCP antibodies are generated and why citrullinated proteins are targeted clinically in conditions such as rheumatoid arthritis. It’s not a reversal of citrulline back to arginine, and citrullination can affect many proteins (not only enzymes) and is indeed linked to cell death processes.

Citrullination is a post-translational modification where arginine residues in proteins are converted to citrulline by peptidylarginine deiminases (PADs). This process occurs more during inflammation and in cells undergoing death (like apoptosis), leading to the appearance of new citrullinated epitopes that anti-CCP antibodies recognize. The statement that arginine is converted to citrulline during apoptosis and that this process increases during inflammation matches the biology of how anti-CCP antibodies are generated and why citrullinated proteins are targeted clinically in conditions such as rheumatoid arthritis. It’s not a reversal of citrulline back to arginine, and citrullination can affect many proteins (not only enzymes) and is indeed linked to cell death processes.