In this paper, we demonstrate a novel pull-down method that dramatically reduces 
the cost and preparation time of a bait protein by cell-free translation with a 
puromycin linker. With the C-terminus of the bait protein linked to biotin 
through a puromycin molecule after the translation reaction and subsequent mRNA 
degradation by RNase, the prey protein was easily pulled down by 
streptavidin-coated magnetic beads in a test tube. Three fluorescent prey 
protein types were tested and confirmed by gel electrophoresis to be pulled down 
easily and rapidly, depending on their affinity.