Trimethyllysine hydroxylase carnitine synthesis

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). 

In general, the effects on collagen synthesis are more marked and more important than those of decreased formation of carnitine (as a result of impaired activity of trimethyllysine and y-butyrobetaine hydroxylases Section 14.1.1), impaired xenobiotic metabolism, or hypercholesterolemia (Section 13.3.8). However, depletion of muscle carititine may account for the lassitude and fatigue that precede clinical signs of scurvy. 

In general, the effects on collagen synthesis are more marked and more important than those of decreased formation of carnitine (as a result of impaired activity of trimethyllysine and y-butyrobetaine hydroxylases Section... 

Trimethyllysine and y-butyrobetaine hydroxylases are required for the synthesis of carnitine (section 5.5.1). 

---