Fludarabine Phosphate is an analogue of adenosine and deoxyadenosine, which is able to compete with dATP for incorporation into DNA and inhibit DNA synthesis.
Fludarabine Phosphate is converted to F-ara-ATP in cells and then incorporated into DNA in a self-limiting manner. Fludarabine Phosphate competes with dATP for incorporation into the A site of the extending DNA strand, which results in termination of DNA strand elongation. Human DNA polymerase α incorporates more Fludarabine Phosphate into DNA than polymerase δ. Fludarabine Phosphate completively inhibits DNA polymerase α and DNA polymerase δ with Ki of 1.1 μM and 1.3 μM, respectively. DNA polymerase δ is also able to excise the incorporated Fludarabine Phosphate from DNA in vitro.