Kinetic analysis of the mode of inhibition of cathepsin L by KGP94, a lead compound from a privileged library of functionalized benzophenone thiosemicarbazone derivatives, demonstrated that it is a time-dependent, reversible, and competitive inhibitor of the enzyme. These results are consistent with the formation of a transient covalent bond, and are supported by molecular modeling that places the thiocarbonyl of the inhibitor in proximity to the thiolate moiety of the enzyme active site Cys25. KGP94 significantly decreased the activity of cathepsin L toward human type I collagen, and impeded both migration and invasion of MDA-MB-231 human breast cancer cells. Growth retardation was achieved in vivo against both recently implanted and established tumours using a C3H mouse mammary carcinoma model.

动力学分析了组织蛋白酶L被KGP94抑制的模式，KGP94是来自功能化的二苯甲酮硫半碳酰胺衍生物的特权文库中的领先化合物，证明其是该酶的时间依赖性，可逆性和竞争性抑制剂。这些结果与瞬时共价键的形成是一致的，并且由分子模型支持，该分子模型将抑制剂的硫代羰基放置在酶活性位点Cys25的硫醇酯部分附近。KGP94大大降低了组织蛋白酶L对人I型胶原的活性，并阻碍了MDA-MB-231人乳腺癌细胞的迁移和侵袭。在体内达到生长迟缓 使用C3H小鼠乳癌模型来针对最近植入的肿瘤和已建立的肿瘤。