Figure 1.

Schematic principle of the improvement of a protein-protein coupling reaction by enzyme surface supercharging. A high volume of wild type enzyme of the human enteropeptidase light chain is required due to its low solubility, resulting in a high total reaction volume and low yield of coupling product (A). Highly soluble surface supercharged human enteropeptidase light chain permits an increase of the enzyme concentration prior to the coupling process (B). Therefore the total reaction volume can be reduced to give a higher yield of desired product (antibody-enzyme conjugate).