The Role of Carbohydrates at the Origin of Homochirality in Biosystems

Pasteur has demonstrated that the chiral components in a racemic mixture
can separate in homochiral crystals. But with a strong chiral discrimination the chiral
components in a concentrated mixture can also phase separate into homochiral fluid
domains, and the isomerization kinetics can then perform a symmetry breaking into
one thermodynamical stable homochiral system. Glyceraldehyde has a sufficient
chiral discrimination to perform such a symmetry breaking. The requirement of
a high concentration of the chiral reactant(s) in an aqueous solution in order to
perform and maintain homochirality; the appearance of phosphorylation of almost
all carbohydrates in the central machinery of life; the basic ideas that the biochemistry
and the glycolysis and gluconeogenesis contain the trace of the biochemical
evolution, all point in the direction of that homochirality was obtained just afteror
at a phosphorylation of the very first products of the formose reaction, at
high concentrations of the reactants in phosphate rich compartments in submarine
hydrothermal vents. A racemic solution of D,L-glyceraldehyde-3-phosphate could
be the template for obtaining homochiral D-glyceraldehyde-3-phosphate(aq) as well
as L-amino acids