The association−dissociation behavior of the ApoE proteins: kinetic and equilibrium studies.

ABSTRACT: The apolipoprotein E family consists of three major protein isoforms: apolipoprotein E4 (ApoE4), ApoE3, and ApoE2. The isoforms, which contain 299 residues, differ only by single-amino acid changes, but of the three, only ApoE4 is a risk factor for Alzheimer’s disease. At micromolar concentrations, lipid-free ApoE exists predominantly as tetramers. In more dilute solutions, lower-molecular mass species predominate. Using fluorescence correlation spectroscopy (FCS), intermolecular fluorescence resonance energy transfer (FRET), and sedimentation methods, we found that the association−dissociation reaction of ApoE can be modeled with a monomer−dimer−tetramer process. Equilibrium constants have been determined from the sedimentation data, while the individual rate constants for association and

SUBMITTER: Garai K 

PROVIDER: S-EPMC3038193 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature