title: Ribonucleotide reductase in blue-green algae: dependence on adenosylcobalamin.
abstract: Ten species of freshwater blue-green algae exhibit an adenosylcobalamin-dependent ribonucleotide reductase, thuse explaining the requirement for cobalt by these organisms. The evidence suggests a phylogenetic affinity between the cyanophytes and bacteria, such as Clostridium and Rhizobium, and the euglenoid flagellates, which also use the cofactor-dependent reductase. In contrast, the ribonucleotide reductase reaction in the few green algae surveyed shows no dependence on cobalamins.
mesh_terms: D005075:Biological Evolution; D000458:Cyanobacteria / Q000201:enzymology* / Q000378:metabolism; D012264:Ribonucleotide Reductases / Q000378:metabolism*; D014805:Vitamin B 12 / Q000378:metabolism*
chemical_list: D012264:Ribonucleotide Reductases; D014805:Vitamin B 12