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Why are all the OH opposite to each other in D and L glucose?

  1. Apr 23, 2012 #1
  2. jcsd
  3. Apr 23, 2012 #2

    Ygggdrasil

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    Because D- and L-glucose are enantiomers (i.e. mirror images), their configuration is switched at all stereocenters of the molecule.
     
  4. Apr 23, 2012 #3
    This makes sense. But then why do we care about the last chiral carbon?
     
  5. Apr 23, 2012 #4

    Ygggdrasil

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    We don't. Like many thing in biology, the choice on how to name the different stereoisomers of glucose is somewhat arbitrary. It just turns out that, if you draw all of the naturally occuring aldohexoses in a Fisher projection, almost all of them have the same configuration about C5, so biochemists chose that position to use as the basis for the D/L nomenclature system.
     
  6. Apr 24, 2012 #5
    You are too kind, sir.
     
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