Ribonucleotide reductase from Rhizobium meliloti has been
partially purified and characterized. The enzymatic reduction of
ribonucleotides to deoxyribonucleotides is dependent upon B₁₂ coenzyme
and dihydrolipoate.
B₁₂ coenzyme was more effective than B₁₂ coenzyme analogues
in the reductase reaction. The affinity of the R. meliloti
reductase system for B₁₂ coenzyme was...