Interaction of rat α‐fetoprotein and albumin with polyunsaturated and other fatty acids: Determination of apparent association constants

Abstract
The interaction of fatty acids with rat α-fetoprotein and albumin was measured using a partition equilibrium method. α-Fetoprotein (AFP) displays one high-affinity binding site for fatty acids and albumin near two binding sites. The AFP association constants for most fatty acids were similar to those of albumin (in the 107 M−1 range) whereas for docosa-hexaenoic acid it was 9.7 × 108 M−1, about 50-fold higher than that corresponding to albumin. This difference justifies docosahexaenoic acid in fetal or neonatal serum being mainly bound to AFP and can indicate a highly specific role of AFP in the transport of this fatty acid.