108315-75-9Relevant articles and documents
Folate Receptor Targeting and Cathepsin B-Sensitive Drug Delivery System for Selective Cancer Cell Death and Imaging
Jin, Xiangmei,Zhang, Jun,Jin, Xiaoyan,Liu, Lan,Tian, Xizhe
, p. 1514 - 1520 (2020)
In this work, a folate receptor (FR)-mediated dual-targeting drug delivery system was synthesized to improve the tumor-killing efficiency and inhibit the side effects of anticancer drugs. We designed and synthesized an FR-mediated fluorescence probe (FA-Rho) and FR-mediated cathepsin B-sensitive drug delivery system (FA-GFLG-SN38). FA-GFLG-SN38 is composed of the FR ligand (folic acid, FA), the tetrapeptide substrate for cathepsin B (GFLG), and an anticancer drug (SN38). The rhodamine B (Rho)-labeled probe FA-Rho is suitable for specific fluorescence imaging of SK-Hep-1 cells overexpressing FR and inactive in FR-negative A549 and 16-HBE cells. FA-GFLG-SN38 exhibited strong cytotoxicity against FR-overexpressing SK-Hep-1, HeLa, and Siha cells, with IC50 values of 2-3 μM, but had no effect on FR-negative A549 and 16-HBE cells. The experimental results show that the FA-CFLG-SN38 drug delivery system proposed by us can effectively inhibit tumor proliferation in vitro, and it can be adopted for the diagnostics of tumor tissues and provide a basis for effective tumor therapy.
Model studies of competing hydrolysis and epimerization of some tetrapeptides of interest in amino acid racemization studies in geochronology
Moir, Michael E.,Crawford, Robert J.
, p. 2903 - 2913 (2007/10/02)
The processes of epimerization of individual peptide units in proteins and the concurrent cleavage of peptide bonds are modelled by heating some tetrapeptide and tetrapeptide derivatives to 148.5 deg C in pH 6.8 phosphate buffer.An excess of D-proline was observed during the heating of L-propyl-L-leucylglycylglycine.The D/L ratio of proline attains a maximum value of 2.1 after 90 minutes.The excess D-proline is attributed to the formation of a 2.3:1 mixture of diketopiperazines cyclo-(D-propyl-L-leucyl) and cyclo-(L-prolyl-L-leucyl).These two species account for most of the leucine and proline in the final mixture after the tetrapeptide is no longer detectable.Only small amounts of prolylleucine can be detcected after 50 hours.It is suggested that the above tetrapeptide undergoes internal aminolysis.Leucine in the tetrapeptide glycyl-L-leucylglycylglycine racemizes three times faster than in L-propyl-L-leucylglycylglycine.This demonstrates that an amino acid residue in a peptide chain does have an effect upon the rate of epimerization of a neighbouring peptide residue.A discussion of the geochemical implications of the results is included.
