NUDT22 inhibitors encompass a variety of compounds that act on different stages of purine metabolism and nucleotide synthesis. These inhibitors do not directly target NUDT22 but rather decrease the availability of its substrates or increase the concentration of competitive inhibitors, which can result in the indirect inhibition of NUDT22 function. For instance, allopurinol and methotrexate target enzymes upstream of purine nucleotide synthesis, which can lead to altered levels of substrates necessary for NUDT22 activity. Specifically, the inhibition of purine synthesis pathways by methotrexate can significantly decrease the levels of nucleotides available for NUDT22 to process.
Similarly, compounds like mercaptopurine and mycophenolic acid disrupt the synthesis and metabolism of purine nucleotides. By doing so, they not only reduce the concentration of substrates for NUDT22 but may also increase the concentration of nucleotide analogs, which can competitively inhibit which can competitively inhibit NUDT22's enzymatic function. Mercaptopurine acts as an antimetabolite that gets incorporated into DNA and RNA, leading to the inhibition of purine nucleotide synthesis. Since NUDT22 is involved in the maintenance of nucleotide pools by hydrolyzing oxidized purine nucleoside diphosphates, the presence of mercaptopurine could lead to the accumulation of these substrates, possibly inhibiting the function of NUDT22 due to substrate overload or competitive inhibition.