Dynamics of Lipoprotein Interconversion

It is now well-established that plasma low-density lipoprotein (LDL) is a final breakdown product of the metabolism of very low-density lipoprotein (VLDL). The process by which LDL is formed in the plasma compartment — the VLDL interconversion process — is mediated through the activity of the enzyme system lipoprotein lipase, and involves compositional, structural, and functional alterations of all major plasma lipoproteins. The purpose of the present discussion is to describe the many events which take place during lipoprotein interconversion and to present a hypothesis on possible molecular mechanisms of the process. Several reviews have been published lately on the structure and composition of lipoproteins (Eisenberg and Levy, 1975; Morrisett et al., 1975; Jackson et al., 1976; Eisenberg, 1976a). These subjects, therefore, will not be dealt with here.