The present invention provides compounds according to Formula I as described herein, and their use for inhibiting the lysine gingipain protease (Kgp) from the bacteriumPorphyromonas gingivalis. Also described are gingipain activity probe compounds and methods for assaying gingipain activity are also described, as well as methods for the treatment of disorders associated withP. gingivalisinfection, including brain disorders such as Alzheimer’s disease.本發明提供如本文中所闡述之式I化合物,及其用於抑制來自細菌牙齦卟啉單胞菌(Porphyromonas gingivalis)之離胺酸牙齦蛋白酶(lysine gingipain protease,Kgp)之用途。亦闡述牙齦蛋白酶活性探針化合物,及亦闡述用於分析牙齦蛋白酶活性之方法,以及用於治療與牙齦卟啉單胞菌感染相關病症,包括諸如阿茲海默氏病(Alzheimer’s disease)之腦病症之方法。