The binding of synthetic retinoids to lipocalin beta-lactoglobulins.

The binding of therapeutically relevant synthetic retinoid derivatives to bovine and reindeer beta-lactoglobulin (beta LG) is demonstrated using fluorescence quenching and ultrafiltration/HPLC methods. Furthermore, synthesis of methyl (E)-3-[4-[(E)-2-(2,6,6-trimethylcyclohex-1-enyl)vinyl]phenyl]-acrylate 4 and (E)-3-[4-[(E)-2-(2,6,6-trimethylcyclohex-1-enyl)vinyl]phenyl]acrylic acid 5 is described. All studied Compounds bind to both beta LG homologues with nanomolar K-d values, and the interaction diminishes the pH-dependent aggregation of retinoids. Thus, beta LG may show benefits ill improving the bioavailability of retinoid derivatives.