"Thomas A. Easton - Life is in the Stars" - читать интересную книгу автора (Easton Thomas A)

the boiling point of water. And even though the complex organic molecules are subject to destruction by
the same energies that produce them, they can survive in the deeper waters of the seas, washed out of
the air and off the hot dry shores by the rains and waves, stored away from excessive heat and ultraviolet
until the next reaction on the way to life.



Figure 2: A sketch of the general type of hardware used in many of the experiments performed to
evaluate the potential of the presumed primordial atmosphere to produce organic material. The
reaction vessel would contain a mixture of such gases as carbon monoxide, carbon dioxide,
ammonia, formaldehyde, methane, ethane, hydrogen, and hydrogen sulfide. The collection vessel
would contain water which would, as the experiment progressed, come to resemble a dilute broth
of many of the organic compounds thought to be necessary for the formation of the first living
cell. The energy applied to the reaction vessel would be heat, ultraviolet light, visible light,
electrical discharges, or radiation.

The famous “dilute soup,” or broth, of the early seas would thus have contained many of the elementary
building blocks of life. But how were these building blocks assembled into the larger molecules of which
cells are built? This question is best illuminated by the study of proteins, for though there are data bearing
on the prebiotic formation of nucleic acids, fats, and carbohydrates, the polymerization of amino acids
into proteins and protein-like molecules is best understood. Because of their role as enzymes in cells,
proteins have been considered as essential to, and even characteristic of, life, and when the chemists
began to look for “organic” chemicals arising from the primitive-Earth conditions, they focused on amino
acids, which also seemed the easiest to produce.

Their efforts have resulted in the abiotic (without life) synthesis of all of the amino acids found in living
things and the demonstration of a simple, plausible way in which they can be linked together, or
polymerized, to form proteins. In the mid-1950s, Sidney Fox, now of the University of Miami, exposed a
dry mixture of assorted amino acids to temperatures of 120 to 200°C and found that they readily
polymerized. Furthermore, if phosphoric acid was added to the mixture, the polymerization would occur
at temperatures as low as 60°C, and that finding made it possible to declare that this way of polymerizing
amino acids was entirely consistent with our picture of the early Earth. If amino acids formed in the
atmosphere or the sea were deposited on rock by rain or waves, or perhaps by the evaporation of pools,
and then dried, volcanic or solar heat would have been enough to produce from them long protein-like
molecules. The conditions would have been particularly suitable along volcanic shores, of which there are
still many on this planet.

The product of this reaction was called “proteinoid” because of its strong resemblance to natural protein.
Not only did it show many of the physical properties of protein, including a molecular size comparable to
that of small protein molecules, but it also proved to nourish bacteria, be digestible by the same enzymes
we use to break down protein, show weakly enzyme-like activities in a number of the reactions important
to metabolism, and have a biological effect similar to that of one hormone which controls coloring in some
animals. These properties were not, of course, all shared by all proteinoids, for Fox could vary the
properties of the proteinoid by varying the amino acids in the initial mixture, thus changing their
susceptibility or resemblance to enzymes and conferring or removing their hormonal activity.

In general, the proteinoids are strikingly reminiscent of the proteins of life. It has been said that they are
“sufficiently like protein in a general sense that (they) could have served as the raw material from which
the powerful and highly specific contemporary enzymes evolved,” and they might have served as
“multifunctional pro-toenzymes,” an “ ‘urprotein’… possessing nonspecific properties common to all