APOBEC1 (Apolipoprotein B mRNA Editing Enzyme, Catalytic Polypeptide 1) is an RNA-editing enzyme that alters apolipoprotein B (apoB) mRNA, resulting in a shorter version of the protein in the intestine. This editing process is crucial for lipid metabolism and lipoprotein formation. Dysregulation of APOBEC1 can affect cholesterol balance and has been associated with research on cardiovascular and lipid-related diseases.