COACERVATES: CHARACTERISTICS, RELATIONSHIP WITH ORIGIN OF LIFE - BIOLOGY - 2025

The coacervates are organized groups of proteins, carbohydrates and other materials in solution. The term coacervate comes from the Latin coacervare and means "cluster". These molecular groupings have some properties of cells; For this reason, the Russian scientist Aleksander Oparin suggested that the coacervates gave rise to these.

Oparin proposed that in primitive seas the appropriate conditions probably existed for the formation of these structures, from the grouping of loose organic molecules. That is, basically the coacervates are considered a precellular model.

Coacervates

These coacervates would have the ability to absorb other molecules, grow and develop more complex interior structures, similar to cells. Later, the experiment of the scientists Miller and Urey allowed to recreate the conditions of the primitive Earth and the formation of the coacervates.

characteristics

- They are generated by grouping different molecules (molecular swarm).

- They are organized macromolecular systems.

- They have the ability to self-separate from the solution where they are, thus forming isolated drops.

- They can absorb organic compounds inside.

- They can increase their weight and their volume.

- They are capable of increasing their internal complexity.

- They have an insulating layer and can be self-preserved.

Relationship with the origin of life

In the 1920s, biochemist Aleksandr Oparin and British scientist JBS Haldane independently established similar ideas about the conditions required for the origin of life on Earth.

They both suggested that organic molecules could form from abiogenic materials in the presence of an external energy source, such as ultraviolet radiation.

Another of his proposals was that the primitive atmosphere had reducing properties: very little amount of free oxygen. In addition, they suggested that it contained ammonia and water vapor, among other gases.

They suspected that the first forms of life appeared in the ocean, warm and primitive, and that they were heterotrophic (they obtained preformed nutrients from the compounds existing in the early Earth) instead of being autotrophic (generating food and nutrients from sunlight. or inorganic materials).

Oparin believed that the formation of the coacervates promoted the formation of other more complex spherical aggregates, which were associated with lipid molecules that allowed them to be held together by electrostatic forces, and that they could have been precursors to cells.

Action of enzymes

Oparin's coacervates work confirmed that enzymes, essential for the biochemical reactions of metabolism, function better when contained within the membrane-bound spheres than when they are free in aqueous solutions.

Haldane, who was unfamiliar with Oparin's coacervates, believed that simple organic molecules formed first and that, in the presence of ultraviolet light, they became increasingly complex, giving rise to the first cells.

The ideas of Haldane and Oparin formed the basis for much of the research on abiogenesis, the origin of life from lifeless substances, that took place in recent decades.

Theory of coacervates

The coacervate theory is a theory expressed by biochemist Aleksander Oparin and which suggests that the origin of life was preceded by the formation of mixed colloidal units called coacervates.

Coacervates are formed when various combinations of proteins and carbohydrates are added to water. Proteins form a boundary layer of water around them that is clearly separated from the water in which they are suspended.

These coacervates were studied by Oparin, who discovered that under certain conditions, coacervates can stabilize in water for weeks if they are given a metabolism, or system to produce energy.

Enzymes and glucose

To achieve this, Oparin added enzymes and glucose (sugar) to the water. The coacervate absorbed the enzymes and glucose, then the enzymes caused the coacervate to combine glucose with other carbohydrates in the coacervate.

This caused the coacervate to increase in size. The waste products of the glucose reaction were expelled from the coacervate.

Once the coacervate became large enough, it spontaneously began to break apart into smaller coacervates. If the structures derived from the coacervate received the enzymes or were able to create their own enzymes, they could continue to grow and develop.

Subsequently, subsequent work by American biochemists Stanley Miller and Harold Urey showed that such organic materials can be formed from inorganic substances under conditions that simulate early Earth.

With their important experiment they were able to demonstrate the synthesis of amino acids (the fundamental elements of proteins), passing a spark through a mixture of simple gases in a closed system.

Applications

Currently, coacervates are very important tools for the chemical industry. Compound analysis is required in many chemical procedures; This is a step that is not always easy and it is also very important.

For this reason, researchers are constantly working to develop new ideas to improve this crucial step in sample preparation. The objective of these is always to improve the quality of the samples before carrying out the analytical procedures.

There are many techniques currently used for pre-concentration of samples, but each, in addition to numerous advantages, also has some limitations. These disadvantages promote the continued development of new extraction techniques more effective than existing methods.

These investigations are also driven by regulations and environmental concerns. The literature provides the basis to conclude that so-called "green extraction techniques" play a vital role in modern sample preparation techniques.

"Green" techniques

The "green" character of the extraction process can be achieved by reducing the consumption of chemicals, such as organic solvents, as these are toxic and harmful to the environment.

Procedures routinely used for sample preparation should be environmentally friendly, easy to implement, inexpensive and have a shorter duration to carry out the entire process.

These requirements are met by applying coacervates in sample preparation, as they are colloids rich in tensile-active agents and also function as an extraction medium.

Thus, coacervates are a promising alternative for sample preparation because they allow concentrating organic compounds, metal ions and nanoparticles in the different samples.

References

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2. Fenchel, T. (2002). The Origin and Early Evolution of Life. Oxford University Press.
3. Helium, L. (1954). Theory of coacervation. New Left Review, 94 (2), 35–43.
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8. Oparin, A. (1965). The Origin of Life. Dover Publications, Inc.