The myTXTL Pro Kit is intended for expression of proteins that do not require disulfide bonds. It also has the highest yield of our two kits. The Antibody/DS Kit is intended for the expression of proteins that do contain disulfide bonds such as antibodies and enzymes. The yield of the Antibody/DS kit varies with the protein expressed, but for deGFP it is about 30-50% the yield of the Pro Kit. This is still enough protein for most downstream applications.