Apob - apolipoprotein B

This gene product is the main apolipoprotein of chylomicrons and low density lipoproteins. It occurs in plasma as two main isoforms, apoB-L and apoB-H. Unlike the apoB-48 and apoB-100 structural equivalents in human, which are synthesized exclusively in the gut and liver, respectively, the rat apoBL isoform is also found in rat liver. The intestinal and the hepatic forms of apoB are encoded by a single gene from a single, very long mRNA. The two isoforms share a common N-terminal sequence. The shorter apoB-L protein is produced after RNA editing of the apoB-H transcript at residue 2180 (CAA->UAA), resulting in the creation of a stop codon, and early translation termination. [provided by RefSeq, Jul 2008]