racemization


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racemization

 [ra″sĕ-mĭ-za´shun]
the transformation of one-half of the molecules of an optically active compound into molecules that possess exactly the opposite (mirror-image) configuration, with complete loss of rotatory power because of the statistical balance between equal numbers of dextrorotatory and levorotatory molecules.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ra·ce·mi·za·tion

(rā'sē-mi-zā'shŭn, rās-mi-),
Partial conversion of one enantiomorph into another (as an l-amino acid to the corresponding d-amino acid) so that the specific optical rotation is decreased, or even reduced to zero, in the resulting mixture.
Farlex Partner Medical Dictionary © Farlex 2012

ra·ce·mi·za·tion

(rā'sĕ-mī-zā'shŭn)
Partial conversion of one enantiomorph into another (as an l-amino acid to the corresponding d-amino acid) so that the specific optic rotation is decreased, or even reduced to zero, in the resulting mixture.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
The process of cationic ROP can produce low-molecular-weight poly lactic acid while anionic ROP process can lead to racemization [15].
Racemization is a chemical process that converts pure enantiomers
The melanoidin pigment, formed during Maillard reaction, might be connected with racemization of amino acids (Kim and Lee, 2008).
This 23-chapter book explores mechanisms linking aging, disease, and biological age estimation, focusing on four of the hallmarks of aging--aspartic acid racemization, advanced glycation endproducts, telomere shortening, and mitochondrial DNA mutations--and their role in aging and diseases and their application in age-at-death estimation in forensic sciences.
For example, measuring the racemization of aspartic acid in collagen from human cartilage and skin, a half-life of 117 years for cartilage collagen and 14.8 years for skin collagen was described [56], whereas in rats a collagen turnover time of 30-150 days was described [57].
Since racemization is not possible during the reaction, this method allows the preparation of enantiopure 1,2,3-benzotriazinones in excellent yields.
Some researchers have found that when peptide is in alkaline condition, it is likely that racemization reaction occurs and reduces the antioxidant activity of MPHs; furthermore, at high pH values, deamination reaction resulting in change with structure, conformation, and loss of antioxidant activity of peptides might occur [40, 41].
Many of these are chiral molecules that can exist in plants in different enantiomeric forms, such as the pepper aroma compound linalool [82], which occurs naturally in one enantiomeric form but experiences racemization during postharvest treatment [75, 83].
Nishida, "Quantitative evaluation of photodegradation and racemization of poly(l-lactic acid) under UV-C irradiation," Polymer Degradation and Stability, vol.
Thus, no detectable racemization took place under the conditions of the Pd-catalyzed vinylation.