Pyridoxal phosphate is the active form of vitamin B6, acts as an inhibitor of reverse transcriptases, and is used for the treatment of tardive dyskinesia.

Pyridoxal 5′-phosphate severely inhibits the DNA Polymerase and RNase H. Pyridoxal phosphate results in an imnediate reduction in the rate of DNA synthesis^[1]. Conjugation to pyridoxal phosphate fully inhibits NEIL2. Pyridoxal phosphate-conjugated NEIL2 shows much lower activity than the intact enzyme over a wide range of enzyme/substrate ratios. After Pyridoxal phosphate conjugation, the ability of NEIL2 to bind the THF-ligand is completely lost^[2].

• [1]. Modak MJ. Pyridoxal 5' phosphate: a selective inhibitor of oncornaviral DNA polymerases. Biochem Biophys Res Commun. 1976 Jul 12;71(1):180-7.

  [2]. Grin IR, et al. Inactivation of NEIL2 DNA glycosylase by pyridoxal phosphate reveals a loop important for substrate binding. Biochem Biophys Res Commun. 2010 Mar 26;394(1):100-5.