L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH.

ABSTRACT: The metabolite 2-hydroxyglutarate (2HG) can be produced as either a D-R- or L-S- enantiomer, each of which inhibits ?-ketoglutarate (?KG)-dependent enzymes involved in diverse biologic processes. Oncogenic mutations in isocitrate dehydrogenase (IDH) produce D-2HG, which causes a pathologic blockade in cell differentiation. On the other hand, oxygen limitation leads to accumulation of L-2HG, which can facilitate physiologic adaptation to hypoxic stress in both normal and malignant cells. Here we demonstrate that purified lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) catalyze stereospecific production of L-2HG via 'promiscuous' reduction of the alternative substrate ?KG. Acidic pH enhances production of L-2HG by promoting a protonated form of ?KG that binds to a key residue in the substrate-binding pocket of LDHA. Acid-enhanced production of L-2HG leads to stabilization of hypoxia-inducible factor 1 alpha (HIF-1?) in normoxia. These findings offer insights into mechanisms whereby microenvironmental factors influence production of metabolites that alter cell fate and function.

SUBMITTER: Intlekofer AM 

PROVIDER: S-EPMC5516644 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature