title: Non-enzymatic chemistry enables 2-hydroxyglutarate-mediated activation of 2-oxoglutarate oxygenases.
abstract: Accumulation of (R)-2-hydroxyglutarate in cells results from mutations to isocitrate dehydrogenase that correlate with cancer. A recent study reports that (R)-, but not (S)-2-hydroxyglutarate, acts as a co-substrate for the hypoxia-inducible factor prolyl hydroxylases via enzyme-catalysed oxidation to 2-oxoglutarate. Here we investigate the mechanism of 2-hydroxyglutarate-enabled activation of 2-oxoglutarate oxygenases, including prolyl hydroxylase domain 2, the most important human prolyl hydroxylase isoform. We observe that 2-hydroxyglutarate-enabled catalysis by prolyl hydroxylase domain 2 is not enantiomer-specific and is stimulated by ferrous/ferric ion and reducing agents including L-ascorbate. The results reveal that 2-hydroxyglutarate is oxidized to 2-oxoglutarate non-enzymatically, likely via iron-mediated Fenton-chemistry, at levels supporting in vitro catalysis by 2-oxoglutarate oxygenases. Succinic semialdehyde and succinate are also identified as products of 2-hydroxyglutarate oxidation. Overall, the results rationalize the reported effects of 2-hydroxyglutarate on catalysis by prolyl hydroxylases in vitro and suggest that non-enzymatic 2-hydroxyglutarate oxidation may be of biological interest.
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Hanna
authors.initials: H
authors.lastname: Tarhonskaya
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Rydzik
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Ivanhoe K H
authors.initials: IK
authors.lastname: Leung
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Nikita D
authors.initials: ND
authors.lastname: Loik
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Mun Chiang
authors.initials: MC
authors.lastname: Chan
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Akane
authors.initials: A
authors.lastname: Kawamura
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: James S O
authors.initials: JS
authors.lastname: McCullagh
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Timothy D W
authors.initials: TD
authors.lastname: Claridge
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Emily
authors.initials: E
authors.lastname: Flashman
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Schofield
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D005977:Glutarates / Q000737:chemistry* / Q000378:metabolism*; D010105:Oxygenases / Q000378:metabolism*; D019802:Succinic Acid / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D005977:Glutarates; C019417:alpha-hydroxyglutarate; D005680:gamma-Aminobutyric Acid; D019802:Succinic Acid; D000429:Alcohol Oxidoreductases; D010105:Oxygenases; C009338:succinic semialdehyde; D001205:Ascorbic Acid