Cell-free synthesis of factor VIII related protein

Polyadenylated ribonucleic acid (RNA) was isolated from confluent human endothelial cells in culture and translated in a cell-free rabbit reticulocyte lysate protein-synthesizing system. Using specific immunoprecipitation, the translation product was found to contain 1.58% VIII related protein (VIII R), which has a molecular weight of 0.26 X 10(6), similar to the subunit of VIII R present in normal plasma. This indicated that VIII R messenger RNA is responsible for the synthesis of subunits only and intracellular post-translational events are required for the assembly of tetramer and multimers.