Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Procollagen, lysine hydroxylase

A number of iron-containing, ascorbate-requiring hydroxylases share a common reaction mechanism in which hydroxylation of the substrate is linked to decarboxylation of a-ketoglutarate (Figure 28-11). Many of these enzymes are involved in the modification of precursor proteins. Proline and lysine hydroxylases are required for the postsynthetic modification of procollagen to collagen, and prohne hydroxylase is also required in formation of osteocalcin and the Clq component of complement. Aspartate P-hydroxylase is required for the postsynthetic modification of the precursor of protein C, the vitamin K-dependent protease which hydrolyzes activated factor V in the blood clotting cascade. TrimethyUysine and y-butyrobetaine hydroxylases are required for the synthesis of carnitine. [Pg.496]

The formation of Hyp and Hyl residues in procollagen is catalyzed by iron-containing oxygenases ( proline and lysine hydroxylase, EC 1.14.11.1/2). Ascorbate is required to maintain their function. Most of the symptoms of the vitamin C deficiency disease scurvy (see p. 368) are explained by disturbed collagen biosynthesis. [Pg.344]

Procollagen lysine 5-dioxygenase [Fe, ascorbate]— lysine hydroxylase ... [Pg.422]

Procollagen proline 4-hydroxylase is the best studied of this class of enzymes it is assumed that the others have essentially the same mechanism, although proline and lysine hydroxylases show very little sequence homology (Kivirikko and Pihlajaniemi, 1998). Although 3-hydroxyproline is found only in collagen, 4-hydroxyproline and hydroxylysine are found in a variety of other proteins, including the Clq component of complement, osteocalcin, macrophage receptor proteins, and a variety of transmembrane and intercellular proteins and proteins of the cytoskeleton, as weU as some enzymes. 4-Hydroxyproline, but not hydroxylysine, also occurs in elastin. [Pg.367]

Peptidyllysine, 2-oxoglularate oxygen 5-oxidoreduc-tase, or Lysine, 2-oxoglutarate dioxygenase, or Lysine hydroxylase (EC 1.14.11.4). It catalyses hydroxylation of lysine residues in procollagen, forming residues of... [Pg.479]

Proline and lysine hydroxylases are required for the post-synthetic modification of procollagen in the formation of mature, insoluble, collagen, and proline hydroxylase is also required for the post-synthetic modification of the precursor proteins of osteocalcin and the Clq component of complement. [Pg.402]

Before this "maturation" can occur there must be other modifications to procollagen. These begin while the peptide chains are still attached to ribosomes of the rough ER. Hydroxylases (Chapter 18) localized in the membranous vesicles of the ER convert some of the proline and lysine residues of the procollagen chains into 4-hydroxyproIine625 629 630 and hydroxylysine (Eqs. 8-6 and 8-7). Lesser amounts of 3-hydroxypro-line are formed. About 100 molecules of 4-hydrox-yproline and 50 of 5-hydroxylysine are created in each al chain. [Pg.432]

Procollagen(I) is an example of a protein that undergoes extensive posttransla-tional modifications. Hydroxylation reactions produce hydroxyproline residues from proline residues and hydroxylysine from lysine residues. These reactions occur after the protein has been synthesized (Fig. 49.3) and require vitamin C (ascorbic acid) as a cofactor of the enzymes, for example, prolyl hydroxylases and lysyl hydroxylase. Hydroxyproline residues are involved in hydrogen bond formation that helps to stabilize the triple helix, whereas hydroxylysine residues are the sites of attachment of disaccharide moieties (galactose-glucose). [Pg.907]


See other pages where Procollagen, lysine hydroxylase is mentioned: [Pg.367]    [Pg.50]    [Pg.367]    [Pg.50]    [Pg.498]    [Pg.266]    [Pg.367]    [Pg.107]    [Pg.108]    [Pg.108]    [Pg.158]    [Pg.185]    [Pg.1063]    [Pg.83]    [Pg.436]    [Pg.102]    [Pg.103]    [Pg.107]    [Pg.218]    [Pg.297]   
See also in sourсe #XX -- [ Pg.367 ]

See also in sourсe #XX -- [ Pg.367 ]

See also in sourсe #XX -- [ Pg.367 ]




SEARCH



Procollagen

Procollagens

© 2024 chempedia.info