(3R,5R)-7-((3R,5R)-7-(2-(4-fluorophenyl)-5-isopropyl-3-phenyl-4-(phenylcarbamoyl)-1H-pyrrol-1-yl)-3,5-dihydroxyheptanamido)-3,5-dihydroxyheptanoic aci

KL-50 is a selective toxin toward tumors that lack the DNA repair protein O6-methylguanine-DNA-methyltransferase (MGMT), which reverses the formation of O6-alkylguanine lesions.

正缬氨酸是一种非蛋白支链氨基酸。此前曾报道它是枯草芽孢杆菌抗真菌肽的天然成分。正缬氨酸和其他修饰的支链氨基酸在最近的研究中受到了关注，因为它们似乎被掺入到大肠杆菌中发现的一些重组蛋白中。