UR-MK299

UR-MK299 is a highly potent and selective small molecule antagonist of the neuropeptide Y (NPY) Y1 receptor (Y1R). Chemically characterized as an argininamide-type compound, it possesses picomolar binding affinity (Kd 0.044 nM) and an exceptionally long target residence time with a half-life of approximately 95 minutes. Developed at the University of Regensburg, UR-MK299 has been a pivotal research tool in G protein-coupled receptor (GPCR) pharmacology, most notably enabling the determination of the human Y1R crystal structure at 2.7 Å resolution. While the Y1 receptor is a target of interest for treating obesity, bone loss, and various tumors, UR-MK299 itself is utilized exclusively for research purposes and has not progressed into clinical trials.