The role of phosphate in the action of thymidine phosphorylase inhibitors: Implications for the catalytic mechanism
作者:Harsh V. Jain、Roshni Rasheed、Thomas I. Kalman
DOI:10.1016/j.bmcl.2010.01.076
日期:2010.3
5-fluoro-6-[(2-aminoimidazol-1-yl)methyl]uracil (AIFU), a potent inhibitor of thymidine phosphorylase (TP) with Ki-values of 11 nM (ecTP) and 17 nM (hTP), are described. Kinetic studies established that the type of inhibition of TP by AIFU is uncompetitive with respect to inorganic phosphate (or arsenate). The results obtained suggest that AIFU and other zwitterionic thymine analog inhibitors of TP act as transition
Synthesis and in Vitro Evaluation of 5-Fluoro-6-[(2-Iminopyrrolidin-1-YL)Methyl]Uracil, TPI(F): An Inhibitor of Human Thymidine Phosphorylase (TP)
作者:John R. Grierson、J. Scott Brockenbrough、Janet S. Rasey、Linda Wiens、Hubert Vesselle
DOI:10.1080/15257770903451603
日期:2010.1
An investigation was conducted to determine if the 5-fluoro analog of TPI (5-chloro-6-[(2-iminopyrrolidin-1-yl)methyl]uracil), a potent inhibitor of human thymidine phosphorylase (TP), has an IC(50) in a range that might allow to use it labeled for imaging of TP expression in vivo. The previously unreported fluoro analog, TPI(F), was prepared and tested against TPI and TPI(Br) using an inhibition assay of [H-3] thymidine cleavage. An assay, performed in the presence of 0.4 mg/ml of human TP, yielded IC(50) values of 2.5 nM, 2.7 nM, and 9.0 nM for TPI, TPI(Br), and TPI(F), respectively. The results indicate that further studies to develop (18)F-labeled TPI(F) as a potential radiopharmaceutical for PET imaging of TP expression in vivo are warranted.