Last month, before Art went out into the field, he had written the following
statement as part of a reply to one of my posts:
"I know this, that for many years Fox tried all kinds of combinations of
amino acids before he hit on one that worked."
At the time I chose to object to the implication that once Fox found a
combination that did work, that he never changed it. I have since, however,
discovered that Art's statement itself is factually incorrect.
As early as 1900 two German chemists reported that they could get aspartic
acid to homopolymerize using heat. A number of scientists reproduced their
results, but since no other amino acid tested could homopolymerize, the
results were largely dismissed as an anomaly. Fox was the first to ask the
question whether other amino acids could polymerize in the presence of
aspartic acid; he called this copolymerization. Obviously, therefore, he
knew before he even began his experiments that aspartic acid would have to be
present if there was any hope that other amino acids would thermally
polymerize; this wasn't something he discovered after a long series of random
experiments..
He first spent some time demonstrating that aspartic acid could copolymerize
with each of the other amino acids individually. Then he did the definitive
experiment that demonstrated that aspartic acid could copolymerize all the
amino acids simultaneously. While he probably tried combinations of amino
acids without aspartic acid, it is not true what Art claims that Fox spent
years trying to find just the right combination that would work. His
preliminary experiments showed both that any amino acids in any combination
would copolymerize with aspartic acid and that diferent amounts of aspartic
acid were equally effective. And once he knew that all amino acids could
copolymerize he began playing around with different mixtures of different
amounts, even some with as low as 10% aspartic acid.
These points bare repeating: Fox did not spend years trying to find just the
right combination of amino acids that would copolymerize and in fact there is
no one combination that is just right. As I have said before, in defiance of
Art's claims that highly controlled conditions are needed to achieve
copolymerization, the only conditions that must be satisfied are the presence
of glycine, aspartate, glutamate, or lysine, and 50-200 degrees Celsius of
heat. Beyond that, virtually anything goes.
Kevin L. O'Brien