Fructose

Left or right: why does nature have such a clear a preference?
Researchers in the US have shown that the presence of spin-polarized electrons can make a
chemical reaction involving “right-handed” molecules occur faster than the same reaction
involving “left-handed” molecules. The discovery could help scientists understand why nature
favors a certain handedness in many biological molecules. So electron spin can directly affect the
formation of the handedness of the biological molecule. So now we have the proof we needed to
show that electron spin is involved in health.
An important question facing those trying to understand the origins of life is why important
biological molecules have a certain handedness or “chirality”? Amino acids, for example, can be
either right- or left-handed mirror-images of each other. However, they are always left handed
when produced by living organisms. This is important because chirality can affect how a molecule
takes part in the chemical reactions crucial for life.
Scientists believe that two external agents could be responsible for chirality in biological molecules:
circularly polarized light and spin-polarized electrons.
Life from outer space?
While circularly polarized light is rare on Earth, astronomers know that it can be produced in the
interstellar medium — leading some to speculate that the precursors to chiral biological molecules
were created in space and somehow transported to Earth. The origin of this homochirality in
biology is the subject of much debate. Most scientists believe that Earth life's "choice" of chirality
was purely random, and that if carbon-based life forms exist elsewhere in the universe, their
chemistry could theoretically have opposite chirality. However, there is some suggestion that
early amino acids could have formed in comet dust. In this case, circularly polarised radiation
(which makes up 17% of stellar radiation) could have caused the selective destruction of one
chirality of amino acids, leading to a selection bias which ultimately resulted in all life on Earth
being homochiral
Low-energy spin-polarized electrons are produced when X-rays and other ionizing radiation strike
iron, nickel and other magnetic materials. These materials are relatively abundant and such
interactions could have occurred on the early Earth, on other planets and even in space.
What is the difference between L-Taurine and Taurine, or between L-Glycine and Glycine?
The natural plant and animal amino acids are typically the “L form”, as in L-arginine, L-cysteine,
etc. Synthetic forms are denoted as “D forms”, such as D-Methionine and D-Carnitine. But there
are 2 aminos that have only one form without these variations: Glycine and Taurine. These two
aminos are sometimes called L-Taurine or L-Glycine, but are more properly called just “Taurine”
and “Glycine”. Regardless of the name used, they are always natural amino acids.
Most aminos have a property that, when the molecule is put into a solution, it will polarize
and rotate light photons either to the left or right. The Greek words denoting left and right are
Levo for left and Dextro for right, so the letters L and D are used to distinguish these forms. This
polarization and rotation of light is called “optical rotation”. The differing L and D forms are called
stereoisomers. For amino acids that polarize light, the L form is the natural form.
However, Taurine is an amino acid that does not polarize light. It thus is properly called just
“Taurine”, without L or D configurations. While some label Taurine as “L-Taurine”, that name
is not technically correct. “Taurine” is the same exact molecule and form as what is commonly
mislabeled as “L-Taurine”. This why taurine is in the energy drinks. Taurine for bull is in the Red
Bull drink.
There is another amino acid that lacks a potential optical rotation. Glycine is a very simple molecule
that comes only as “Glycine”, also lacking different L or D stereoisomer forms. Glycine, Glutamic
acid and Taurine can cross the blood brain barrier easier for this reason. They act as secondary
suppliers of energy to the brain cells. And thus are key components of the energy drink.
The D forms of amino acids sold commercially are considered to be synthetic. However, D forms of
amino acids are not always synthetic. There are several D forms that exist in nature. In addition,
amino acids can be racemized by the body and go back and forth between the D form and the
L form quite easily. However, only L forms can be incorporated into proteins. For the purposes
of dietary supplements, the L forms are natural and the D forms are synthetic. DLPA and DLmethionine
are actually racemic mixtures of both L and D forms.
But there is no such thing as D-Taurine or D-Glycine; in other words, no synthetic forms exist of
these two aminos since each only comes as one isomer that doesn’t polarize and rotate light to
the right. Nor are there really L forms of these, since they do not polarize and rotate light to the
left, either. There are simply single, natural isomers of just plain Glycine and Taurine.
Don’t assume that all D or L forms of molecules are good or bad, since it really depends on the
individual substance concerned. For example, the D isomers of vitamin E are the natural forms
140 141