Cobamides and ribonucleotide reduction. 3. Factors influencing the level of cobamide-dependent ribonucleoside triphosphate reductase in Lactobacillus leichmannii.

摘要: Abstract The specific and total activities of ribonucleoside triphosphate reductase in extracts Lactobacillus leichmannii are increased as the period linear growth culture before harvesting is increased. Extracts from cells harvested toward end phase have highest activity, activity lower longer time delayed beyond this point. Stationary give without significant activity. increase extended appears to indicate a rapid rate synthesis since chloramphenicol actinomycin D arrest increase. decrease stationary does not appear result presence an amount proteolytic enzymes nor incomplete liberation enzyme such cells. L. at when higher concentrations deoxyribosyl compounds or cyanocobalamin present medium. This interpreted indicating that act corepressors indirectly represses through its ability intracellular pool acid-soluble compounds. Neither thymine deoxyribose causes repression enzyme.