Kinetic analysis of iron-dependent histone demethylases: α-ketoglutarate substrate inhibition and potential relevance to the regulation of histone demethylation in cancer cells.
The Jumonji C domain-containing histone demethylases (JmjC-HDMs) are α-ketoglutarate (αKG)-dependent, O(2)-activating, non-heme iron enzymes that play an important role in epigenetics. Reported herein is a detailed kinetic analysis of three JmjC-HDMs, including the cancer-relevant JMJD2C, that was achieved by employing three enzyme activity assays. A continuous O(2) consumption assay reveals that HDMs have low affinities for O(2), suggesting that these enzymes can act as oxygen sensors in vivo. An interesting case of αKG substrate inhibition was found, and the kinetic data suggest that αKG inhibits JMJD2C competitively with respect to O(2). JMJD2C displays an optimal activity in vitro at αKG concentrations similar to those found in cancer cells, with implications for the regulation of histone demethylation activity in cancer versus normal cells.
Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899, United States.
Barbara
B
Cascella
Liviu M
LM
Mirica
D044127:Epigenesis, Genetic; D056466:Histone Demethylases; D056484:Jumonji Domain-Containing Histone Demethylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007656:Ketoglutaric Acids / Q000494:pharmacology; D007700:Kinetics; D010101:Oxygen Consumption
C413655:KDM4C protein, human; D007656:Ketoglutaric Acids; D056466:Histone Demethylases; D056484:Jumonji Domain-Containing Histone Demethylases; C549811:KDM4E protein, human; C494424:KDM4A protein, human