Transformation into Expression Host BL21(DE3) For transforming into the expression host BL21(DE3), use 1-2 pl of the pET-44 plasmid (50 ng/ul) and follow your transformation procedure. After the heat shock and dilution, spread cells on LB and LB-Amp plates and incubate overnight at 37°C. Using 100 ng of pET-44 with the competent BL21(DE3) cells, approximately 500 colonies should be obtained per plate with your transtormation procedure You Setting wil up be for provided.