1,1'-Ethylene-bis(1-nitrosourea)(EBNU)の生化学的研究(第7報)EBNUおよび関連化合物のラット肝臓クロマチンの鋳型活性に及ぼす影響

抄録

The binding of 1, 1'-ethylene-bis (1-nitrosourea) (EBNU), 1-methyl-1-nitrosourea (MNU), and 1-ethyl-1-nitrosourea (ENU), labeled their alkyl groups with ¹⁴C, to rat liver chromatin was compared in vitro. The alkylating activity to chromatin decreased in the order of MNU, EBNU, and ENU. The effects of nine N-nitrosoureas (three bis-N-nitrosoureas, five mono-N-nitrosoureas, and chloroethyl-N-nitrosourea) on the template activity of rat liver chromatin and E. coli DNA were compared by using exogenous bacterial DNA-dependent RNA polymerase system. The inhibition on the template activity of rat liver chromatin was dependent on the concentration of EBNU and on the time course of alkylation in the case of MNU and EBNU. The template activity was inhibited by EBNU, 1, 1'-propylene-bis (1-nitrosourea), MNU, ENU, and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. The inhibitory effects had a tendency to decrease with increasing the length of alkyl chain. The inhibitory effects to E. coli DNA were stronger than those to rat liver chromatin. The template activity of rat liver chromatin was slightly increased by 1, 1'-hexamethylene-bis (1-nitrosourea), 1-isobutyl-1-nitrosourea, and potassium cyanate.