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C5H9O3N An amino acid that is essentially limited to structural proteins of the collagen type.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Hydroxyproline Measurement: Hydroxyproline levels in wet tissues (mg/g) were measured using the method described by Hutson et al (7) with some modifications.
Proline and hydroxyproline (OHP) are present in various amounts in certain structural proteins, such as high in collagen and low in elastin [1].
Hydroxyproline that constitutes the main component of collagen plays an important role in the collagen stabilization (25).
To determine whether FSTL1 expression is aberrant in progressive lung fibrotic diseases, we induced PF in C57BL/6 mice through bleomycin intratracheal administration.[24] Lung sections showed significant tissue structural damage and inflammatory cell infiltration 14 days after bleomycin injury [Figure 1]a and concomitant collagen accumulation in lung tissues as determined by hydroxyproline content measurement [Figure 1]b.
No significant differences in tissue hydroxyproline levels at the EGJ were found when the four groups were compared with each other separately (p=0.92) and when they are compared as combined 12-Fr and 8-Fr groups (p=0.59) (Table 4).
They are often combined with other vitamins and ingredients such as Type 2 hydrolysates and glucosamine for joint health; for example, low molecular weight Bio Cell is combined with proline hydroxyproline and vitamin C for healthy skin and hair.
Lung Coefficient, Wet/Dry, and Hydroxyproline Level.
The proximate composition and hydroxyproline content were measured on fresh muscle tissue samples, whereas the amino acid profile was determined in samples stored at -36[degrees]C.
However, there are many examples in which silylation reactions are actually slow in pyridine, for instance, with hydrophilic amino acids such as proline and hydroxyproline [28].

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