The ability of thioredoxin (Trx) to protect cells from chemical damage was
determined by comparing the growth of a control strain of Escherichia coli
JM101 and isogenic strain transformed with the plasmid pKKTS1 containing th
e Streptomyces aureofaciens thioredoxin gene, in the presence of the nucleo
side analogs arabinosylcytosine, 5-fluorouridine, ftorafur and carcinogen b
eta-naftylamine. Arabinosylcytosine showed no effect on the growth of eithe
r of the two strains. 5-fluorouridine, ftorafur [1-((R, S)-tetrahydrofuran-
2-yl)-5-fluorouracil] and beta-naftylamine demonstrated lower inhibitory ef
fects on the growth of the thioredoxin overproducing strain than on the gro
wth of the control strain. These results suggested that Trx could protect t
he cells from chemical damage under certain metabolic conditions.