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Proline in collagen

Vitamin C Cosubstrate in the hydroxylation of proline in collagen. Deficiency leads to... [Pg.199]

Ascorbic acid is a vitamin in primates. In most other animals, it can be synthesized by a branch of the glucoronic acid pathway (Chapter 18). It is apparently not changed into any coenzyme in the human being and participates as a vitamin in a reducing capacity in several biochemical reactions. These include the post-translational hydroxylation of proline in collagen biosynthesis (Chapter 8) and in tyrosine metabolism (Chapter 20). Ascorbic acid is oxidized to dehydroascorbic acid, a diketo derivative of ascorbate. Scurvy is a deficiency disease caused by a shortage of dietary ascorbic acid. In children, this results in defective bone formation in adults, extensive bleeding occurs in a number of locations. Scurvy is to be suspected if serum ascorbic acid levels fall below 1 jug/mL. [Pg.138]

Figure 16.7 Fluorinated prolines in collagen, (a) The trans/cis isomerization of amide bonds and main-chain angles of proline residues. The n —> interaction, depicted by a dashed line,... Figure 16.7 Fluorinated prolines in collagen, (a) The trans/cis isomerization of amide bonds and main-chain angles of proline residues. The n —> interaction, depicted by a dashed line,...
It is a cofactor of prolyl and lysyl hydroxylase enzymes in the first stages of collagen synthesis these are necessary for the inclusion of proline in collagen. [Pg.341]

Table 6.2 lists the amino acid compositions of four different fibrous proteins, namely ot-keratin, fibroin, collagen, and elastin. Notice the relatively high abundance of amino acids with non-bulky side chains, such as glycine, alanine, serine, glutamate, and glutamine. A notable exception to this is the quite high amount of proline in collagen and, to a lesser extent, in elastin. Each of the proteins in Table 6.2, however, has a unique amino acid composition, because each is comprised of a unique sequence of amino acids. [Pg.1590]

In proteins, there occur 20 amino acids, which take part in ribosome-mediated protein synthesis. Many non-standard amino acids, however, are found in a variety of proteins the best known of them being trans-4-hydroxyl-L-proline (in collagen) omitted in Table 1. These additional amino acids arise from modifications of the side chains in polypeptides after synthesis by the normal... [Pg.8]

These mechanisms for the synthesis of glycine present a partial barrier to the movement of FA carbons into this molecule, the most abimdant AA in collagen. On the other hand, proline is synthesized from a-keto glutarate which can be freely derived from either carbohydrates or FAs thus the synthesis of pro line does not present a barrier to entry ofFA-derived carbons into collagen. [Pg.194]

C Ascorbic acid Coenzyme in hydroxylation of proline and lysine in collagen synthesis antioxidant enhances absorption of iron Scurvy—impaired wound healing, loss of dental cement, subcutaneous hemorrhage... [Pg.482]

The hydroxyl group is added to proline after synthesis into protein and is only found in collagen and gelatine — has two asymmetric carbon atoms... [Pg.345]

Another important 2-OG dependent oxygenase in mammals is prolyl-4 hydroxylase, which catalyzes the hydroxylation of the proline residue in collagen (Scheme 5). This reaction is essential for the structure of the collagen triple helices (9,34 6). An overproduction of collagen is related to fibrotic diseases such as rheumatic arthritis. Thus collagen prolyl-4 hydroxylase is a target for therapeutics (34,36). [Pg.107]

Ascorbic acid Tight Ascorbic acid (C) Maintains reduced state of iron atom in enzymes involved in hydroxylation of proline and lysine in collagen... [Pg.33]

Cell metabolism induction. Methanol extract of STE, in collagen-producing cells, stimulated glycolysis by 80% in cartilage but was not affected in the other tissues. Medium alkaline phosphatase activity was unaffected. In the frontal bone and cartilage, [ H]hydroxyproline and [ H]proline contents were decreased. Neither was affected in the aorta. [Pg.297]

In addition to the 20 common amino acids, proteins may contain residues created by modification of common residues already incorporated into a polypeptide (Fig. 3-8a). Among these uncommon amino acids are 4-hydroxyproline, a derivative of proline, and 5-hydroxylysine, derived from lysine. The former is found in plant cell wall proteins, and both are found in collagen, a fibrous protein of connective tissues. 6-N-Methyllysine is a constituent of myosin, a contractile protein of muscle. Another important uncommon amino acid is y-carboxyglutamate, found in the bloodclotting protein prothrombin and in certain other proteins that bind Ca2+ as part of their biological function. More complex is desmosine, a derivative of four Lys residues, which is found in the fibrous protein elastin. [Pg.80]


See other pages where Proline in collagen is mentioned: [Pg.1374]    [Pg.649]    [Pg.125]    [Pg.461]    [Pg.440]    [Pg.721]    [Pg.1374]    [Pg.649]    [Pg.125]    [Pg.461]    [Pg.440]    [Pg.721]    [Pg.174]    [Pg.197]    [Pg.143]    [Pg.147]    [Pg.38]    [Pg.240]    [Pg.183]    [Pg.185]    [Pg.187]    [Pg.187]    [Pg.336]    [Pg.298]    [Pg.274]    [Pg.231]    [Pg.475]    [Pg.493]    [Pg.494]    [Pg.495]    [Pg.497]    [Pg.60]    [Pg.62]    [Pg.311]    [Pg.22]    [Pg.508]    [Pg.389]    [Pg.280]    [Pg.112]    [Pg.434]    [Pg.130]    [Pg.131]    [Pg.313]   
See also in sourсe #XX -- [ Pg.2 , Pg.4 , Pg.30 ]

See also in sourсe #XX -- [ Pg.1141 ]

See also in sourсe #XX -- [ Pg.415 , Pg.417 ]




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