Fatty acid binding protein. Isolation from rat liver, characterization, and immunochemical quantification.

Area of Science:

• Biochemistry
• Molecular Biology
• Cellular Metabolism

Background:

• Fatty acid-binding proteins (FABPs) are involved in intracellular fatty acid transport and metabolism.
• Understanding FABP's role is key to comprehending cellular lipid handling.

Purpose of the Study:

• To identify and characterize fatty acid-binding protein (FABP) from rat liver cytosol.
• To investigate the relationship between FABP concentration and fatty acid utilization in hepatocytes.

Main Methods:

• Isolation and purification of FABP using gel filtration, isoelectric focusing, and affinity chromatography.
• Analysis of FABP's amino acid composition and bound fatty acids.
• Quantification of FABP concentration via radial immunodiffusion.

Main Results:

• FABP was isolated with a molecular weight of 12,080 +/- 80 Da and exists in multiple forms.
• FABP-bound fatty acids constituted 60% of total cytosolic fatty acids, with enrichment in 18:2 and 20:4.
• FABP concentration was significantly higher in female rats compared to males (p < 0.05).

Conclusions:

• FABP plays a significant role in the cytosolic binding and metabolism of long-chain fatty acids.
• FABP abundance correlates with fatty acid utilization rates in hepatocytes.
• Sex-based differences in FABP levels suggest a role in sex steroid-modulated fatty acid metabolism.