Figure A. Purified recombinant GFP and RFP resolved by SDS-PAGE and stained with Coomassie blue. Lanes 1 and 2: 50 and 25 ng, respectively, of purified RFP; lane 3: 50 ng of purified GFP. Figure B. Immunoblot. Lanes 1 and 2: 12.5 and 4 ng of RFP; lane 3: 50 ng of GFP. Some cross reactivity of the RFP with GFP is observed due to the presence of the 6-His tag on GFP. RFP was used at 1:30,000 dilution and the HRP-conjugated rabbit anti-chicken antibody was used at 1:10,000. Bands were visualized using ECL.