背景资料：Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 2 (APOBEC2) is a 224 amino acid protein that belongs to the cytidine and deoxycytidylate deaminase family. Expressed exclusively in heart and skeletal muscle, APOBEC2 is thought to be a probable C (cytidine) to U (uridine) editing enzyme. However, unlike other members of the family, such as APOBEC1, which mediates the editing of apolipoprotein (apo) B mRNA, APOBEC2 does not display any detectable apoB mRNA editing activity. Also, APOBEC2 has been shown to have low, but definite, intrinsic cytidine deaminase activity.