[Isolation of cellular retinol-binding protein from cattle liver]

Cellular retinol-binding protein from bovine liver has been purified to homogeneity. The protein binds retinol with high affinity; the apparent dissociation constant was determined by fluorometric titration to be 2.18 x 10(-3) M. Retinol bound to the protein has an absorption spectrum (lambda max = 350 nm) and considerably differs from the spectrum of retinol absorption in ethanol (lambda max = 325 nm). The protein is a single polypeptide chain with a molecular weight of approximately 14 kDa based on information obtained by sodium dodecyl sulfate-polyacrylamide electrophoresis.