ApoB-48 + 40 triacylglycerol + 60 phospholipid => ApoB-48:TG:PL complex Authored: D'Eustachio, P, 2007-04-30 14:19:38 Edited: D'Eustachio, P, 2006-02-20 18:35:05 GENE ONTOLOGYGO:0042158 Phospholipid (PL) and triacylglycerol (TG) associate with the apo B-48 polypeptide as it is translated. This process is mediated by MTP (microsomal triacylglycerol transfer protein) in the form of a MTP:PDI (protein disulfide isomerase) heterodimer. MTP in vitro binds small amounts of PL and TG (annotated here as as one molecule of each) and efficiently transfers the bound lipid between membranes (Atzel and Wetterau 1994). In vivo, MTP:PDI directly interacts with apoB-48 polypeptide (Wu et al. 1996), and is thought to transfer lipid from the endoplasmic reticulum membrane to nascent apoB-48. While some of the molecular details of MTP function remain unclear, this function is clearly essential in vivo, as patients who lack MTP cannot produce chylomicrons (e.g., Wetterau et al. 1992; Narcisi et al. 1995). Pubmed1439810 Pubmed14732096 Pubmed7803401 Pubmed8533758 Pubmed8626595 Reactome Database ID Release 43174786 Reactome, http://www.reactome.org ReactomeREACT_6908 has a Stoichiometric coefficient of 40 has a Stoichiometric coefficient of 60 ApoB-48:TG:PL complex