Fig. 1: Reactions catalysed by FIH.

FIH is a 2OG oxygenase catalyzing the posttranslational C3 hydroxylation of (L)-residue substrates including the hypoxia-inducible factor α-subunits (HIFα; R = CONH₂) and ankyrin repeat domain proteins (R = CONH₂, COOH, OH, imidazole and isopropyl) to give mono-hydroxylated products. Note all studied (L)/(2S)-substrates give products with the same relative stereochemistry at C3, i.e., (2S,3S) for R = CONH₂, COOH, Imidazole, OH or (2S,3R) for R = ⁱPr.