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C5H9O3N An amino acid that is essentially limited to structural proteins of the collagen type.



4-hydroxy-2-pyrrolidinecarboxylic acid, a heterocyclic amino acid (in terms of chemical structure, an imino acid).

Hydroxyproline was first isolated from gelatin hydrolyzates in 1902 by E. Fischer. Because of the presence of two asymmetric carbon atoms per molecule, it has four optically active forms (L-, D-, allo-L-, and allo-D-hydroxyprolines) and two racemic forms. Natural L-hydroxyproline is a specific constituent of proteins in connective tissue, collagen and elastin (up to 13 percent), as well as of certain vegetable proteins; other proteins contain negligible amounts of L-hydroxyproline or none at all. Allo-L-hydroxypro-line was discovered in free form in sandalwood and is a component of toxic peptides in the death-cap. The formation of L-hydroxyproline in living cells is effected by hydroxylation of the proline bonded to the protein components (the O atom of the hydroxyl group is incorporated into hydroxyproline upon fixation of molecular O2). One of the products formed during the conversion of L-hydroxyproline in the organism is glutamic acid.

References in periodicals archive ?
Notably, hydroxyproline is highly specific for collagen, and hydroxyproline measurement accurately reflects the amount of collagen in the tissue (Ferreira et al.
The mean hydroxyproline values increased significantly in all the groups of animals with a significant difference between the groups and within the group.
Hydroxyproline content of lung tissue was determined by colorimetric method as described by Edwards and O'Brien [20].
The concentrations of the amino acids cysteine, methionine, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, histidine, ornithine, lysine, arginine, hydroxyproline, tryptophan and taurine were nearly identical in kapenta compared to FPC (Table 1).
This collagen protein contains only 2 binding pockets and the amino acids such as proline & hydroxyproline are present in these pockets.
This conversion process involves the hydroxylation of proline at certain points in the polypeptide chains, converting it to hydroxyproline, and thus "securing" the chains in collagen's triple helix arrangement.
The three major constituent amino acids are glycine, proline and hydroxyproline, which represent about 45% of the total composition.
2]-dependent cross-linking of cell wall proteins such as hydroxyproline rich glycoproteins and proline-rich proteins (Bestwick et al.
Hydroxyproline is only formed from proline when this has been incorporated into the newly synthesised collagen--and proline itself is, in any case not an essential amino acid, so it is not a question of nutritional deficiency.
mansoni infected outbred Swiss mice caused a decrease in hepatic fibrosis levels as compared to untreated animals (represented by liver hydroxyproline values) after two days of treatment.
Leucine, isoleucine, alloisoleucine, and hydroxyproline all have molecular weights of about 131 and are quantitated together for this reason.

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