because dna polymerase-alpha is the third dna replication enzyme ( the others are ribonucleotide reductase and thymidylate synthase ) that has been shown to depend on parathyroid hormone and/or the circulating levels of calcium and 1,25 ( oh ) 2d3 that it controls , the authors concluded that the processes dependent on calcium and 1,25 ( oh ) 2d3 are parts of a mechanism that coordinately activates the dna-replicating enzymes .
C0598312
dna replication
C0035547
ribonucleotide reductase