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

Enzymes
Application of Enzymes

Possessing a high degree of selectivity, Enzymes are utilized by living organisms to drive a vast array of Chemical Reactions at remarkable speeds; they retain their catalytic activity not only within the microenvironment of The Cell, but also outside the Organism. Enzymes have found widespread application in such industries as baking, brewing, winemaking, tea production, leather and fur Processing, cheesemaking, and culinary meat tenderization, among others. In recent years, enzymes have been increasingly employed in fine chemical synthesis to drive organic reactions such as oxidation, reduction, deamination, decarboxylation, dehydration, and Condensation, as well as for the resolution and isolation of L-amino acid isomers (chemical synthesis typically yields racemic mixtures of L- and D-isomers), which are in high demand across industry, agriculture, and medicine. Mastering the subtle MECHANISMS OF ENZYME action will undoubtedly unlock boundless potential for the large-scale, high-speed laboratory production of valuable compounds with nearly 100% yields.

A new branch of science, industrial enzymology—the cornerstone of modern biotechnology—is currently undergoing rapid development. An enzyme covalently attached ("anchored") to any organic or inorganic polymeric carrier (matrix) is referred to as immobilized. Enzyme Immobilization techniques address several key challenges in enzymology: ensuring high catalytic Specificity and enhanced stability, ease of handling, reusability, and Structure/175.html">Implementation in continuous-flow synthetic reactions. The industrial application of these techniques is known as enzyme engineering. Numerous Examples illustrate the immense potential of enzyme engineering across various sectors of industry, medicine, and agriculture. Specifically, immobilized ß-galactosidase attached to a magnetic stirring rod is used to reduce the milk sugar content in milk—making it suitable for infants afflicted with hereditary lactose intolerance, who cannot digest this disaccharide. Furthermore, milk treated in this manner exhibits a significantly extended shelf life when frozen and does not undergo thickening.

Projects have been developed to produce foodstuffs from Cellulose, specifically by converting it using immobilized enzymes—cellulases—into glucose, which can subsequently be processed into starch. In principle, enzyme technology also makes it possible to obtain nutritional products, particularly CARBOHYDRATES, from liquid Hydrocarbons (petroleum) by cleaving them down to glyceraldehyde, followed by enzyme-catalyzed Synthesis of glucose and starch. Another promising frontier is the biomimetic modeling of Photosynthesis using enzyme engineering—namely, the natural process of CO₂ fixation; alongside immobilization, this vital process for humanity will necessitate The Development of novel, creative methodologies and the application of specialized immobilized Coenzymes.

As an illustration of enzyme immobilization and industrial application, the diagram below outlines a continuous process for producing The amino acid Alanine and regenerating a coenzyme (specifically, NAD) within a model system. In this setup, the starting substrate (lactic acid) is pumped into a Reactor chamber containing NAD⁺ and two NAD-dependent dehydrogenases—Lactate dehydrogenase and Alanine Dehydrogenase—immobilized on a dextran matrix. The reaction product, alanine, is continuously harvested from the opposite end of the reactor at a controlled rate via ultrafiltration.

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Reactors of this type have found utility in the pharmaceutical industry, for instance, in the Synthesis of the anti-rheumatic drug prednisolone from hydrocortisone. Furthermore, they can serve as models for synthesizing and supplying essential metabolic factors, since immobilized Enzymes and Coenzymes allow for the directed execution of coupled chemical reactions (including the Biosynthesis of Essential metabolites), thereby compensating for metabolic deficiencies caused by hereditary disorders. Thus, driven by this novel methodological approach, science is taking its first steps toward "synthetic biochemistry."

Equally critical research directions include cell immobilization and the creation—via Introduction/32.html">Genetic Engineering techniques—of industrial microbial strains designed to overproduce Vitamins and Essential Amino Acids. One notable medical application of biotechnology is the immobilization of thyroid Cells to assay thyroid-stimulating hormone in biological fluids or tissue extracts. On the horizon is the biotechnological production of non-caloric sweeteners—sugar substitutes that impart a sweet taste without contributing high caloric loads. One such promising compound is aspartame, a methyl ester of the dipeptide aspartylphenylalanine (discussed previously). Aspartame is nearly 300 times sweeter than sugar, completely safe, and metabolized in the body into naturally occurring free amino acids: aspartic acid (aspartate) and phenylalanine. Aspartame is destined for widespread adoption in both medicine and the food industry (in the United States, for instance, it is used in infant foods and added as a sugar substitute to diet sodas). Manufacturing aspartame through genetic engineering requires not only producing free aspartic acid and phenylalanine as precursors, but also obtaining the bacterial enzyme that catalyzes The biosynthesis of this dipeptide.

The Significance of enzyme engineering, much like BIOTECHNOLOGY AS A whole, is poised to grow exponentially in the future. According to expert projections, the global output of all biotechnological processes across the chemical, pharmaceutical, and food industries, as well as medicine and agriculture, is expected to reach tens of billions of dollars annually by the year 2000. In our country, the recombinant production of L-Threonine and vitamin B₂ is slated for implementation by 2000. Production of several enzymes, Antibiotics, and a₁-, ß-, and у-interferons is projected to begin as early as 1998, while Insulin and Growth Hormone preparations are currently undergoing clinical trials. Furthermore, domestic hybridoma technology has successfully established The production of Reagents for enzyme-linked immunosorbent assays (ELISA) used to quantify numerous chemical components in biological fluids.