title: Modeling of palmitate transport in the heart.
abstract: Transport of palmitate from the albumin-palmitate complex in the plasma to inside mitochondria where it undergoes beta-oxidation is a multistep process. Albumin's large size prevents permeation via interendothelial clefts. Palmitate dissociation from albumin in solution is too slow to provide an adequate supply of the unbound palmitate. The discovery that the dissociation occurs upon albumin binding to an endothelial surface receptor resolves the conundrum. Palmitate transport across the luminal surface membrane may be either carrier-mediated or passive. Fatty-acid binding protein inside endothelial and cardiac muscle cells facilitates diffusion through cytosol while maintaining the unbound palmitate concentration at a very low level. Within the interstitium, albumin is again the palmitate carrier. Still controversial is whether or not there is a saturable sarcolemmal transporter or simply passive exchange. Inside the myocyte palmitate is again bound to the fatty acid binding protein which buffers the free palmitate concentration, facilitates diffusion, and may facilitate further intracellular reactions.
authors.affiliation: Center for Bioengineering, University of Washington, Seattle.
authors.forename: J B
authors.initials: JB
authors.lastname: Bassingthwaighte
authors.forename: L
authors.initials: L
authors.lastname: Noodleman
authors.forename: G
authors.initials: G
authors.lastname: van der Vusse
authors.forename: J F
authors.initials: JF
authors.lastname: Glatz
mesh_terms: D000818:Animals; D001692:Biological Transport; D002199:Capillary Permeability; D002352:Carrier Proteins / Q000378:metabolism; D004058:Diffusion; D004730:Endothelium, Vascular / Q000378:metabolism; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism*; D009363:Neoplasm Proteins; D010168:Palmitates / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D009363:Neoplasm Proteins; D010168:Palmitates; D010169:Palmitic Acids; D025521:Tumor Suppressor Proteins