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Hydroxyproline is a major component of the protein collagen, [3] comprising roughly 13.5% of mammalian collagen. Hydroxyproline and proline play key roles for collagen stability. [4] They permit the sharp twisting of the collagen helix. [5]
Procollagen-proline dioxygenase catalyzes the following reaction: L-proline + alpha-ketoglutaric acid + O 2 → (2S, 4R)-4-hydroxyproline + succinate + CO 2. The mechanism for the reaction is similar to that of other dioxygenases, and occurs in two distinct stages: [3] In the first, a highly reactive Fe(IV)=O species is produced.
Hence, the hydroxylation of proline is a critical biochemical process for maintaining the connective tissue of higher organisms. Severe diseases such as scurvy can result from defects in this hydroxylation, e.g., mutations in the enzyme prolyl hydroxylase or lack of the necessary ascorbate (vitamin C) cofactor.
One process is a one-step mechanism in which proteins from the cytoplasm of bacteria are transported and delivered directly through the cell membrane into the host cell. Another involves a two-step activity in which the proteins are first transported out of the inner cell membrane, then deposited in the periplasm , and finally through the outer ...
Adams E; Goldstone A (1960). "Hydroxyproline metabolism. III. Enzymatic synthesis of hydroxyproline from Delta1-pyrroline-3-hydroxy-5-carboxylate".
Proline oxidase, or proline dehydrogenase, functions as the initiator of the proline cycle. Proline metabolism is especially important in nutrient stress because proline is readily available from the breakdown of extracellular matrix (ECM), and the degradation of proline through the proline cycle initiated by proline oxidase (PRODH), a mitochondrial inner membrane enzyme, can generate ATP.
In enzymology, a 4-hydroxyproline epimerase (EC 5.1.1.8) is an enzyme that catalyzes the chemical reaction trans -4-hydroxy-L-proline ⇌ {\displaystyle \rightleftharpoons } cis -4-hydroxy-D-proline Hence, this enzyme has one substrate , trans-4-hydroxy-L-proline , and one product , cis-4-hydroxy-D-proline .
The biochemical mechanism of proline racemase was first put forward in the late sixties by Cardinale and Abeles [6] using the Clostridium sticklandii enzyme, CsPRAC. The catalytic mechanism of proline racemase was late revisited by Buschiazzo, Goytia and collaborators that, in 2006, resolved the structure of the parasite TcPRAC co-crystallyzed with its known competitive inhibitor - pyrrole ...