Vitamin D transport - the nature of the interaction between plasma DBP and tissue protein

The plasma-binding protein for vitamin D and its metabolites (DBP) is bound with high affinity (KA approximately 10(7) M-1) and specificity by a 40,000-dalton protein which is a proven constituent of all tissue cytosols examined. This association may be important for in vivo sterol transfer, but its role is currently not defined.