Pooled plasma samples from human subjects homozygous for the T/T allele was adjusted to 1.21 g/ml with NaBr and subjected to density ultracentrifugation. The lipoprotein-free bottom was collected, dialyzed against PBS and immunoprecipitated with anti-apoA-V IgG. The precipitated proteins were solubilized in sample treatment buffer, electrophoresed under non-reducing conditions, transferred to a PVDF membrane and probed for apoA-V as described in Materials and Methods. Lane 1, recombinant apoA-V standard (1.5 ng); lane 2, T/T sample immunoprecipitate (molecular weights indicated on left).