racemization


Also found in: Dictionary, Encyclopedia, Wikipedia.

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.

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.

racemization

/ra·ce·mi·za·tion/ (ra″sĕ-mĭ-za´shun) the transformation of one half of the molecules of an optically active compound into molecules having exactly the opposite configuration, with complete loss of rotatory power because of the statistical balance between the equal numbers of dextro- and levorotatory molecules.

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.

racemization

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.
References in periodicals archive ?
Since D isomers have no nutritional value, racemization of an essential amino acid thus severely reduces its nutritional value [23].
The dating of Unit 1 and the lower parts of Units 2 and 3 is a problem for several reasons: a) the radiocarbon ages of the overlying units show that they are beyond the scope of this method, and b) the organic matter content is too low and contamination by terrigenous materials too high to use uranium/thorium (U/Th) methods (demonstrated by an analysis performed during the development of this research); c) no calcareous remains are preserved due to the acid of composition of soils, so neither palaeontological nor amino-acid racemization methods can be used.
Because of racemization, his preparation contains a mixture of L- and D-thyroxine.
Thaler's] study is significant because it marks the first time that racemization has been looked on as a sign of life on other planets," emphasizes Andreas Bommarius, professor of biomolecular engineering.
We have purified from rat brain a soluble enzyme that catalyzes the direct racemization of L-serine to D-serine.
However, other mechanisms include racemization, photodegradation, elimination, and complexation.
The typogenetic constructional options for changing the monotelic into the polytelic organization-type are thus truncation, homogenization, racemization and disjunction, terms which were proposed by Maresquelle & Sell (1965) and Seil (1976), see also Kunze (1989).
Miller GH, Magee JW, full AJT (1997) Low-latitude glacial cooling in the Southern Hemisphere from amino-acid racemization in emu eggshells.
This suggests that the chemical processing steps needed to synthetically produce L-theanine, or those required to extract pure L-theanine from tea biomass (if not cost-prohibitive) result in racemization.
Pollen studies suggest that the highest RSL occurred during a cooler climate interval after the thermal maximum (~125 ka;), verified by the single OSL date on the Cape George sand and amino acid racemization (AAR) and electron spin resonance (ESR) dating of shell faunas.
8]BINOL (2) is more acidic, more resistant to racemization under a wide variety of conditions, and, perhaps most interestingly, it is pseudo enantiomeric to regular BINOL.