Proline,2-Oxoglutarate Dioxygenases

Proline, 2-Oxoglutarate Dioxygenases.—Part of the enzymic activity was lost when the proline, 2-oxoglutarate dioxygenase from chicken embryos interacted with [ H-acetyl]concanavalin A, suggesting that the enzyme contains a carbohydrate component.  

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Prolyl 4-hydroxylation is the most abundant posttranslational modification of collagens. 4-Hydroxylation of proline residues increases the stability of the triple helix and is a key element in the folding of the collagen triple helix. " In vertebrates, almost all the Yaa position prolines of the Gly-Xaa-Yaa repeat are modified to 4(I( )-hydroxylproline by the enzyme P4H (EC 1.14.11.2), a member of Fe(II)- and 2-oxoglutarate-dependent dioxygenases. This enzyme is an 0 2/ b2-type heterotetramer in which the / subunit is PDI (EC 5.3.4.1), which is a ubiquitous disulfide bond catalyst. The P4H a subunit needs the 13 subunit for solubility however, the 13 subunit, PDI, is soluble by itself and is present in excess in the ER. Three isoforms of the a subunit have been identified and shown to combine with PDI to form [a(I)]2/ 2) [< (II)]2/32> or [a(III)]2/32 tetramers, called the type... 

This enzyme [EC 1.14.11.7], also known as procolla-gen proline, 2-oxoglutarate 3-dioxygenase, catalyzes the reaction of a prolyl residue in procoUagen with dioxygen and a-ketoglutarate (or, 2-oxoglutarate) to produce a irans-3-hydroxyprolyl residue in procollagen, succinate, and carbon dioxide. This reaction also requires iron ions and ascorbate. 

Hara, R., Kino, K. (2009). Characterization of novel 2-oxoglutarate dependent dioxygenases converting L-proline to cis-4-hydroxy-L-proline. Biochem. Biophys. Res. Commun., 379,882-886. 

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