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Date: | Tue, 8 Dec 1998 10:41:51 +0100 |
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Hello,
> When I look at the sugars making up an "average" honey (Hive and the
> Honeybee) I see that one of the major sugars is dextrose (which is
> d-glucose) or right handed glucose in the way it will reflect
> polarized light as I understand it.
Not quite. The indicator D in D-glucose refers just to the sterical
architecture of the molecule (to be exact: just to one of several
sterical centres) and has 'nothing' to do with the direction polarized
light is turned. In this particular case, you are right. D-glucose is
turned polarized light to the right, therefore the usual writing is
D-(+)-glucose, with the (+) indicating the direction to the right.
I used the quotaton marks with 'nothing' because L-glucose
necessarily turns the light the other way round, which is (-).
There are substances, like e.g. lactid acid, which are either
D-(-) or L-(+) and others that are either D-(+) or L-(-).
The name invertase refers to the fact that this enzyme splits
sucrose (D-(+)-Saccharose) into b-D-(-)-fructose and a-D-(+)-glucose.
As D-fructose turns polarized light more to the left than D-glucose does
turn it to the right, the direction of the polarize light is inverted
with regard to a solution of sucrose.
Best wishes,
Michael
--
Michael Haberl
Hessische Landesanstalt fuer Tierzucht, Abt. Bienenzucht
Erlenstr. 9, 35274 Kirchhain, Germany
Tel: ++49-6422-9406-12
Fax: ++49-6422-9406-33
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