Identification of a Thioredoxin Induced by Bacteriophage T4

Infection of Escherichia coli with bacteriophage T4 was previously shown to induce the synthesis of two new proteins involved in the reduction of ribonucleoside 5'-diphosphates to deoxyribonucleoside 5'-diphosphates. One of these proteins has now been purified to homogeneity and was characterized as a thioredoxin. The other protein is a new ribonucleotide reductase. T4 thioredoxin has a molecular weight of around 10,500. It is reduced by thioredoxin reductase from uninfected E. coli. In its reduced form, T4 thioredoxin is the specific hydrogen donor of the T4-induced ribonucleotide reductase.