The main fatty acid-binding protein in the liver of the shark (Halaetunus bivius) belongs to the liver basic type - Isolation, amino acid sequence determination and characterization

Three fatty acid-binding proteins (FABPs) from the liver of the shark Halae tunus bivius were isolated and characterized: one of them belongs to the li ver-type FABP family and the other two to the: heart-type FABP family. The complete primary structure of the first FABP, and partial primary structure s of the two others, were determined. The liver-type FABP constitutes 69% o f the total FABPs, and its amino acid sequence presents the highest identit y with chicken, catfish, iguana and elephant fish liver basic FABPs. The L- FABP protein has low affinity for palmitic and oleic acids and high affinit y for linoleic and arachidonic acids and other hydrophobic ligands, all of them important for the metabolic functions of the liver. In contrast, both heart-type FABPs have the highest affinity for palmitic acid, the principal fatty acid mobilized from fat deposits for beta-oxidation.