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An example of such an enantiomer is the sedative thalidomide, which was sold in a number of countries around the world from 1957 until 1961. It was withdrawn from the market when it was found to cause birth defects. One enantiomer caused the desirable sedative effects, while the other, unavoidably [23] present in equal quantities, caused birth ...
Macroscopic examples of chirality are found in the plant kingdom, the animal kingdom and all other groups of organisms. A simple example is the coiling direction of any climber plant, which can grow to form either a left- or right-handed helix. In anatomy, chirality is found in the imperfect mirror image symmetry of many kinds of animal bodies.
For a chiral molecule with one or more stereocenter, the enantiomer corresponds to the stereoisomer in which every stereocenter has the opposite configuration. An organic compound with only one stereogenic carbon is always chiral. On the other hand, an organic compound with multiple stereogenic carbons is typically, but not always, chiral.
An enantiopure drug is a pharmaceutical that is available in one specific enantiomeric form. Most biological molecules (proteins, sugars, etc.) are present in only one of many chiral forms, so different enantiomers of a chiral drug molecule bind differently (or not at all) to target receptors.
Homochirality can also refer to enantiopure substances in which all the constituents are the same enantiomer (a right-handed or left-handed version of an atom or molecule), but some sources discourage this use of the term. It is unclear whether homochirality has a purpose; however, it appears to be a form of information storage. [2]
The drug was withdrawn from world market when it became evident that the use in pregnancy causes phocomelia (clinical conditions where babies are born with deformed hand and limbs). Later in late 1970s studies indicated that the (R)- enantiomer is an effective sedative, the (S)-enantiomer harbors teratogenic effect and causes fetal abnormalities.
In general, only one of the two enantiomers occurs naturally (for example, D-glucose) and can be metabolized by animals or fermented by yeasts. The term "hexose" sometimes is assumed to include deoxyhexoses , such as fucose and rhamnose : compounds with general formula C 6 H 12 O 6− y that can be described as derived from hexoses by ...
The name theanine usually refers to the enantiomer L-theanine, which is the form found in tea leaves from which it is extracted as a powder. [4] [6] The right-handed enantiomer, D-theanine, is less-studied. Theanine is sold as a dietary supplement and is considered to be safe at doses up to 250 milligrams (mg) by the US Food and Drug ...