Acyl-CoA-binding protein (ACBP) can mediate intermembrane acyl-CoA transport and donate acyl-CoA for β-oxidation and glycerolipid synthesis

Abstract

The dissociation constants for octanoyl-CoA, dodecanoyl-CoA and hexadecanoyl-CoA binding to acyl-CoA-binding protein (ACBP) were determined by using titration microcalorimetry. The K(D) values obtained, (0.24 ± 0.02) x 10-6 M, (0.65 ± 0.2) x 10-8 M and (0.45 ± 0.2) x 10-13 M respectively, were much lower than expected. ACBP was able to extract hexadecanoyl-CoA from phosphatidylcholine membranes immobilized on a nitrocellulose membrane. The acyl-CoA/ACBP complex formed was able to transport acyl-CoA to mitochondria or microsomes in suspension, or to microsomes immobilized on a nitrocellulose membrane, and to donate them to β-oxidation or glycerolipid synthesis in mitochondria or microsomes, respectively.