Vitamin oxoglutarate-linked hydroxylases

Table 13.1 Vitamin C-Dependent 2-Oxoglutarate-Linked Hydroxylases ...

Vitamin C-Dependent 2-Oxoglutarate-linked Hydroxylases Plasma and Leukocyte Ascorbate Concentrations as Criteria of Vitamin C Nutritional Status 13.3. Reference Intakes of Vitamin C... 

As shown in Table 13.1, a number of iron-containing hydroxylases share an unusual reaction mechanism in which hydroxylation of the substrate is linked to decarboxylation of 2-oxoglutarate. Proline and lysine hydroxylases are required for the postsynthetic modification of collagen, and proline hydroxylase also for the postsynthetic modification of osteocalcin (Section 5.3.3) and other proteins. Aspartate /3-hydroxylase is required for the postsynthetic modification of protein C, the vitamin K-dependent protease that hydrolyzes activated Factor V in the blood clotting cascade (Section 5.3.2). Trimethyllysine and y-butyrobetaine hydroxylases are required for the synthesis of carnitine (Section 14.1.1). 

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