Catalysis corresponds to the lowering of the activation energy required for chemical and biological reactions. Catalytic lowering of the required amount of energy is made possible by a catalyst, which in biology corresponds to an enzyme. In enzymatic diseases, the catalytic properties of enzymes may be reduced or even abolished.
What is catalysis?
Catalytic reduction of the amount of energy required is made possible by a catalyst, which in biology corresponds to an enzyme. Figure shows ribbon model of a lipase. Enzymes have specific roles in the human body. As different as the function of individual enzymes may seem, they all basically have the same task and bring similar properties to fulfill this task. The main task of all enzymes is catalysis. This is why biochemistry attributes catalytic properties to them. Literally translated, catalysis means “dissolution.” At the heart of catalysis is the activation energy. As such, chemistry refers to the amount of energy that is absolutely necessary in a reaction system for the chemical reaction of both reaction partners. Catalysts are used to reduce the activation energy and thus allow both reaction partners to undergo a reaction in the reaction system even at low energies. In biological reaction systems, enzymes with catalytic properties thus lower the activation energy of a particular chemical reaction and act accordingly as chemical catalysts. In the context of catalysis, on the one hand the probability of a successful reaction process increases and on the other hand the speed of the reaction sometimes also increases. A shift in the chemical equilibrium does not occur in the course of catalysis. Chemistry distinguishes homogeneous catalysis from heterogeneous catalysis. Biocatalysis corresponds neither to the one nor to the other form. It is an independent form of catalysis.
Function and task
Biocatalysis corresponds to the guidance, conversion, or acceleration of chemical reactions in the biological environment. Enzymes act as biological catalysts in this process. Each enzyme is largely composed of proteins, some of which are associated with a cofactor. Almost all biochemical reactions in living organisms have an enzymatic catalyst. Biocatalysis is implemented in biotechnology by means of isolated or living enzymes. An example of biocatalysis can be found in beer breweries, where biocatalytic processes are implemented using bacteria, fungi or yeasts. The pharmaceutical industry uses biocatalysis to realize otherwise impracticable reactions. In the human body, catalysts are constantly taking place in which enzymes accelerate certain reactions. Enzymes are, for example, relevant to the metabolism of organisms and largely control biochemical reactions in metabolic processes. They control digestion, for example, but are also involved in the transcription and replication of DNA in the form of polymerases. The majority of all biochemical reactions would occur at negligibly slow rates in a living organism without enzymes. Enzymes accelerate the achievement of chemical equilibrium without changing anything about the equilibrium. An enzyme has catalytic activity because it can lower the activation energy in chemical reactions. This energy corresponds to the amount of energy that must be applied in advance to initiate a reaction. During the reaction, the substrate changes to energetically unfavorable transition states. The activation energy forces the substrate into its transition state. The catalytic action of enzymes intervenes at this point in the reaction by stabilizing the transition state of the substrate via non-covalent interactions. In this way, significantly less energy is required to convert a substrate to the transition state. For this reason, the substrate converts to the final product of the reaction at a higher rate. With these catalytic functions, enzymes are considered to be the giving elements for any biochemical reaction product.
Diseases and disorders
When enzymes mutate or fail to adequately perform their catalytic role for other reasons, extensive health consequences set in.The disease group of metabolic diseases includes various disorders from the area of intermediate operating metabolism. Such disorders are either congenital or acquired. Metabolic diseases vary widely in their extent and prevalence. They also manifest themselves clinically in a highly heterogeneous manner. One such disorder is the widespread common disease diabetes mellitus. However, this group of diseases also includes much rarer hereditary diseases with a lethal course. Osteopenia and the resulting osteoporosis are also attributable to metabolic disorders. Most congenital diseases from the superordinate group of metabolic diseases correspond to genetically determined enzyme defects of various enzymes. Depending on the enzyme affected, its catalytic function and its reaction product, enzymatic defects or enzyme deficiencies can cause organs to fail, for example. A relatively rare and congenital metabolic disorder is Gaucher’s disease. The enzyme involved in this disease is glucocerebrosidase or glucocerebrosidase. In a healthy organism, this enzyme degrades aged components of the cell membrane. In Gaucher disease, there is a deficiency of this important enzyme. If the enzyme does not show sufficient activity, deposition of membrane components within the lysosomes occurs. More than 200 mutations of the enzyme have been documented in Gaucher disease to date. The degree of residual enzymatic activity depends on the mutation of the coding gene in each individual case. For example, the disease can cause a complete loss of function of the enzyme. However, a functionally weak reduction of enzymatic activity is also conceivable. Most patients of the disease show manifestations with respect to the internal organs as well as with respect to the nervous system.
