Bovine fatty acid binding proteins. Isolation and characterisation of two cardiac fatty acid binding proteins that are distinct from corresponding hepatic proteins.
When a 100,000 X g supernatant from bovine heart was incubated with [1-14C]oleic acid and subjected to isoelectric focusing, two fatty acid binding proteins (FABPs) with isoelectric points at 4.9 and 5.1 were detected. The proteins were purified on a large scale first by heat and acid precipitation of a postmitochondrial supernatant, as well as fractionation with ammonium sulfate, then by alternate application of ion-exchange and gel chromatography. The procedure afforded around 60 mg pure proteins from 1.5 kg fresh heart muscle. Relative molecular masses of 15 300 +/- 1600 for both proteins were derived from sodium dodecyl sulfate/polyacrylamide gel electrophoresis, gel chromatography, sedimentation velocity as well as from amino acid analysis. Up to 50% of the proteins' secondary structures consisted of beta-sheet. N-termini of the peptide chains were blocked; the amino acid compositions of the two proteins were similar, but differed considerably from those of the two FABPs isolated from bovine liver [Haunerland et al. (1984) Hoppe Seyler's Z. Physiol. Chem. 365, 365-376]. Whereas hepatic FABPs changed their pI upon binding fatty acids, cardiac FABPs did not. Cardiac FABPs were immunologically identical, but did not cross-react with hepatic proteins. A reversible, concentration-dependent self-association reported for FABP from pig heart [Fournier et al. (1983) Biochemistry 22, 1863-1872] was not observed for FABP from bovine heart. Changes of concentration did not alter secondary structure, intrinsic fluorescence or the sedimentation coefficient of the protein.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification*; D002417:Cattle; D002942:Circular Dichroism; D003600:Cytosol / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D050556:Fatty Acid-Binding Proteins; D007120:Immunochemistry; D007525:Isoelectric Focusing; D008099:Liver / Q000032:analysis*; D008970:Molecular Weight; D009206:Myocardium / Q000032:analysis*; D009363:Neoplasm Proteins; D009928:Organ Specificity; D013050:Spectrometry, Fluorescence; D014461:Ultracentrifugation
D000596:Amino Acids; D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins