Ribonucleoside Triphosphate Reductase from L. leichmannii

The reductase from L. leichmannii acts only upon the nucleoside triphosphates and has an absolute requirement for adenosylcobalamin as a coenzyme. This reductase has been purified to homogeneity using conventional purification techniques (70, 71). The enzyme is also retained on an adenosylcobalamin-Sepharose column in the presence of a dithiol and dGTP, a positive effector, and can be removed from the affinity column when dGTP is omitted from the elution buffer. Unfortunately 

In contrast with the reductase from E. coli, the ribonucleotide reductase system from L. leichmannii does not have an absolute requirement for Mg+2 (52, 80). 

Ribonucleoside Triphosphate Reductase from Euglena gracilis 

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