The shuttling of dolichol between VLDL and HDL: involvement of a protein factor from lipoprotein-deficient human serum.

The occurrence of a dolichol transfer factor in LPDS has been demonstrated using three different transfer assays. Applying a three step purification procedure, the transfer factor could be enriched 4000-5000-fold with a recovery of 1-2%. SDS-gel electrophoresis revealed a molecular weight of 64 kDa. Kinetics as well as the influence of a series of effectors were studied. Transfer was not accompanied by a concurrent esterification and the HDL3 subpopulation showed the highest acceptor capacity. The transfer factor also affected liposomal stability based on calcein fluorescence dequenching upon release. The characteristics of this dol-TP are discussed in view of these other plasma LTPs. Dol-TP might play a role in dolichol transfer from VLDL to HDL, observed in vivo.