Biological Chemistry - Berezov T. T., Korovkin B. F. 1998

Enzymes
A Brief History of the Development of Enzymology

Fermentation and Digestion have been known since ancient times, yet the Water/144.html">Origin of the science of Enzymes (enzymology) dates back to the first half of the 19th century. The first scientific concept of enzymes was put forward as early as 1814 by the St. Petersburg scientist K.S. Kirchhoff, who demonstrated that not only germinated barley grains, but also malt extracts, are capable of saccharifying starch, converting it into maltose. The substance extracted from germinated barley that possesses The ability to convert starch into maltose was named amylase. J. Liebig and F. Wöhler discovered an agent that cleaves amygdalin found in bitter almond essential oil. This agent was named emulsin. In subsequent years, Other Enzymes were described, in particular Pepsin and Trypsin, which cause the breakdown (Hydrolysis) of Proteins in the digestive tract.

Researchers have paid the greatest attention to oxidation processes within the living Organism. The phenomenon of chemical catalysis was already known, meaning that many in vitro reactions proceed rapidly and vigorously in the presence of trace amounts of impurities that appear not to participate in the reaction. Thus, the significant catalytic role of A number of inorganic substances was established. The combustion of glucose in air, for example, proceeds very slowly, but if a small amount of lithium salts (or ash, which also contains trace amounts of lithium) is added, the combustion proceeds quite intensively:

Class="center">С₆Н₁₂О₆ + 6O₂ → 6С0₂ + 6Н₂О.

It is known that in living organisms, "combustion" (or more precisely, oxidation) of CARBOHYDRATES also proceeds rapidly and yields the same final metabolic products, i.e., СО₂ and Н₂О, with the release (and accumulation) of energy. However, this "combustion" occurs at a relatively low Temperature, without a flame, and, what is particularly interesting, in the Presence of water. Naturally, under these unusual conditions, carbohydrate oxidation would not occur without the action of enzymes, which have been designated as biological catalysts. Anticipating somewhat, we note that The process of glucose conversion (oxidation) in the organism to СО₂ and Н₂О involves approximately 15 different enzymes acting sequentially (see Chapter 10).

Biological catalysts, i.e., enzymes, turn out not to induce Side Reactions, unlike inorganic catalysts, and do not participate in reactions that are thermodynamically impossible; both types of catalysts merely accelerate Chemical Reactions that usually proceed very slowly. An example is the decomposition reaction of hydrogen peroxide into oxygen and water, which proceeds slowly in the absence of a catalyst. Upon The addition of finely divided platinum, The rate of this reaction increases dramatically:

This same reaction will proceed much faster in the presence of the enzyme catalase, which is contained, in particular, in erythrocytes, yielding the same final products of hydrogen peroxide breakdown.

Thus, it can be considered established that enzymes catalyze a number of chemical reactions analogous to those catalyzed by inorganic substances. Moreover, it is considered established that any chemical reaction occurring in living organisms (or Cells) can, in principle, be carried out outside the organism (or Cell) if the experimenter succeeds in isolating the corresponding enzyme (or enzyme system) catalyzing the given reaction and creating optimal conditions for its action.

Horizons of Enzymology. Literature increasingly features works attempting to forecast the further development of enzymology for the coming decade. Let us list the main research directions of future enzymology. Firstly, these are studies of the finer details of the molecular mechanism and Introduction/14.html">Principles of Enzyme action in accordance with the laws of classical organic chemistry and quantum mechanics, as well as The Development of a theory of Enzymatic Catalysis on this basis. Secondly, The Study of enzymes at higher levels (supramolecular and cellular) of the Structural Organization of living systems, focusing not so much on individual enzymes as on enzyme complexes within complex systems. Thirdly, the investigation of mechanisms regulating enzyme activity and synthesis, and THE CONTRIBUTION OF chemical modification to enzyme action. Fourthly, research will develop in the field of creating artificial low-molecular-weight enzymes—synzymes (synthetic enzyme analogs) that possess high substrate Specificity and catalytic activity similar to native enzymes, but lack adverse antigenic properties. Fifthly, research in the field of engineering enzymology (Protein Engineering), the creation of "hybrid" catalysts combining the METABOLISM/8.html">Properties of Enzymes, Antibodies, and receptors, as well as the creation of biotechnological reactors involving individual enzymes or multienzyme complexes to secure the yield and production of the most valuable Materials and agents for the national economy and medicine. Finally, research in medical enzymology, the primary goal of which is to elucidate the molecular foundations of hereditary and somatic human diseases caused by defects in enzyme synthesis or impaired Regulation of enzyme Activity.