Catalytic Properties of the Asparaginyl Hydroxylase (FIH) in the Oxygen Sensing Pathway Are Distinct from Those of Its Prolyl 4-Hydroxylases

作者：Peppi Koivunen, Maija Hirsilä, Volkmar Günzler, Kari I. Kivirikko, Johanna Myllyharju · 发表于：Journal of Biological Chemistry · 年份：2004 · DOI：10.1074/jbc.m312254200 · 被引用次数：449 · 研究领域：Cancer, Hypoxia, and Metabolism、High Altitude and Hypoxia、Metabolomics and Mass Spectrometry Studies

The activity of hypoxia-inducible transcription factor HIF, an alphabeta heterodimer that has an essential role in adaptation to low oxygen availability, is regulated by two oxygen-dependent hydroxylation events. Hydroxylation of specific proline residues by HIF prolyl 4-hydroxylases targets the HIF-alpha subunit for proteasomal destruction, whereas hydroxylation of an asparagine in the C-terminal transactivation domain prevents its interaction with the transcriptional coactivator p300. The HIF asparaginyl hydroxylase is identical to a previously known factor inhibiting HIF (FIH). We report here that recombinant FIH has unique catalytic and inhibitory properties when compared with those of the HIF prolyl 4-hydroxylases. FIH was found to require particularly long peptide substrates so that omission of only a few residues from the N or C terminus of a 35-residue HIF-1alpha sequence markedly reduced its substrate activity. Hydroxylation of two HIF-2alpha peptides was far less efficient than that of the corresponding HIF-1alpha peptides. The K(m) of FIH for O(2) was about 40% of its atmospheric concentration, being about one-third of those of the HIF prolyl 4-hydroxylases but 2.5 times that of the type I collagen prolyl 4-hydroxylase. Several 2-oxoglutarate analogs were found to inhibit FIH but with distinctly different potencies from the HIF prolyl 4-hydroxylases. For example, the two most potent HIF prolyl 4-hydroxylase inhibitors among the compounds studied were the least effe...