QUENCHING OF TYROSINE RADICALS OF M2 SUBUNIT FROM RIBONUCLEOTIDE REDUCTASE IN TUMOR-CELLS BY DIFFERENT ANTITUMOR AGENTS - AN EPR STUDY

被引：17

作者：

LIERMANN, B

LASSMANN, G

LANGEN, P

机构：

[1] Central Institute of Molecular Biology, Academy of Sciences, GDR, GDR- 1115 Berlin-Buch

来源：

FREE RADICAL BIOLOGY AND MEDICINE | 1990年 / 9卷 / 01期

关键词：

Antitumor agents; EHRLICH ascites tumor cells; Enzyme inhibition; EPR; Free radicals; Hydroxyurea; Ribonucleotide reductase; Thiosemicarbazones; Tyrosine radicals;

D O I：

10.1016/0891-5849(90)90042-H

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The inhibition of ribonucleotide reductase (RR) of intact Ehrlich ascites tumor cells by different antitumor agents was compared using EPR spectroscopy. The inactivation of M2 subunit was measured via quenching of the functionally essential tyrosine radical. Inhibitors of different classes, for example, hydroxyurea, pyrogallol, and thiosemicarbazones, differ in their efficiency by three orders magnitude. Most effective inhibition was found for isoquinoline-1-aldehyde-thiosemicarbazone (IQ-1) with an IC50 value of 0.18 μM. Inhibition of RR inside tumor cells is comparable with that reported for isolated enzymes. © 1990.

引用

页码：1 / 4

页数：4

共 26 条

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