Study On Mechanism Of A Novel Glutamete Dehydrogenase Inhibitor With Antitumor Activity

Human glutamate dehydrogenase(GDH)plays an important role in neurological diseases,tumor metabolism,and hyperinsulinism–hyperammonemia syndrome(HHS).However,there are very few inhibitors known for human GDH.In this paper,the human glutamate dehydrogenase was successfully cloned and expressed in E.coli.ebselen was identified as a GDH inhibitor based on the protein,and ebselen could inhibit both human GDH and E.coli GDH well.Furthermore,the anti-tumor activity of ebselen was verified and it was found that ebselen inhibited the growth of A549 and H22 cell well.Then the mechanism of ebselen inhibits both human and E.coli GDH was studied.The molecular interaction analysis was performed using laboratory synthesized biotin-labeled ebselen derivatives,subsequently,gel shift assay was performed using laboratory synthesized fluorescein-labeled ebselen derivatives,they all showed that ebselen can cross-link with E.coli GDH but not human GDH.Proteomic analysis confirmed that ebselen can bind to the amino acid residues near the active site of the enzyme,suggesting that the specific binding site may be a cysteine residue on the fragment which is very close to NADP~+,this hypothesis is consistent with the point mutation results of the enzyme.