PHD3 (Egl nine homolog 3; Hypoxia-inducible factor prolyl hydroxylase 3; HIF-prolyl hydroxylase 3; HIF-PH3; HPH-1; Egln3; Prolyl hydroxylase domain-containing protein 3;)Catalyzes the post-translational formation of 4-hydroxyproline in hypoxia-inducible factor (HIF) alpha proteins. Hydroxylates HIF-1 alpha at 'Pro-564', and HIF-2 alpha. Functions as a cellular oxygen sensor and, under normoxic conditions, targets HIF through the hydroxylation for proteasomal degradation via the von Hippel-Li