@vpeptides so the gamma-glutamyl was linked to two lysins in the chain? Learn something every day. What I am wondering how the gila monster poison (exendin-4) was added to this chain. I am going into look up a natural GLP-1 and the gila monster/exendin-4 /GLP-1 side by side. They say the moded gila blocks dpp-4 and last longer in the system. What is in the chain or not that allows it to work/express the way it does in reta?