Abzyme, an Important Artificial Synthetic Enzyme

The development of artificial synthetic enzymes is still in the initial stage, and significant progress has been made after several years of efforts. The artificial enzyme developed has a catalytic speed close to that of natural enzymes, which means that the speed of chemical reactions can be increased by more than 100 million times (natural enzymes are usually 10 billion to 1000 billion times). As long as it is properly designed, the catalytic speed of artificial synthetic enzymes can continue to increase. This is enough to show that in the field of enzyme engineering research, artificial synthetic enzymes are promising. The study of artificial synthetic enzymes is of great significance. On the one hand, artificial synthetic enzymes have opened up a way to increase the speed of biochemical reactions. On the other hand, through the study of enzymatic reactions and the development of artificial enzymes, new chemical synthesis routes can be designed to produce cheaper biochemical products. With the development of artificial enzyme research, the ideal of synthesizing starch and protein in factories will become a reality. Synthesis of active enzymes in the laboratory is one of the most interesting and challenging topics for biochemists and chemists. Since the 1980s, with the rapid increase of knowledge about the structure of enzymes and the mechanism of action of enzymes, as well as the continuous improvement of experimental techniques and methods, some breakthroughs have been made in the field of artificial enzyme research. The most important of these are abzymes and hybridases. Abzymes, which appeared in the late 1980s, are the product of an ingenious combination of the high selectivity of antibodies and the efficient catalytic ability of enzymes. It is essentially a class of immunoglobulins with catalytic activity, which endows the properties of enzymes in the variable region, so it is also called catalytic antibody. Antibodies with catalytic activity can be obtained by using pre-designed antigens (haptens) according to the preparation procedures of general monoclonal antibodies. The preparation methods of abzyme include induction method, introduction method, copy method and so on. So far, in addition to the hydrolysis of ester, carboxylic acid and amide bonds, there are more than 10 kinds of reactions catalyzed by abzymes, such as amide formation, photo-induced cleavage and polymerization, and transesterification. The specificity of the enzyme-catalyzed reaction of these antibodies is equivalent to or even exceeds the specificity of the enzyme reaction, and some of the catalysis rates can reach the level of enzyme catalysis. As we all know, both antibodies and enzymes are protein molecules, and the binding of enzymes to substrates and the binding of antibodies to antigens are highly specific. But the fundamental difference between these two binding forms is that enzymes bind to high-energy transition-state molecules, while antibodies bind to antigens (ground-state molecules). Both antibodies and enzymes are macromolecular substances, each performing different missions in the long evolutionary process. Although their structures are very different, they have two things in common: they are both proteins and they can bind to target molecules with high selectivity. Antibodies specifically bind to the antigen and help macrophages to ingest and destroy the antigen. Enzymes can highly selectively combine substances with specific structures in the chemical reaction process, thereby greatly reducing the activation energy of chemical reactions, and catalyzing chemical reactions with high selectivity and efficiency, enabling them to be realized under mild conditions. Antibodies are proteins synthesized by animals to defend against foreign invasion. Abzymes refer to catalytically active antibodies prepared by a series of chemical and biological methods. Inspired by Pauling's transition state theory and predictions, Jencks proposed in 1969 that if an antibody can bind to the transition state product of a chemical reaction, such an antibody must have catalytic properties. This means that once the antibody can bind to the transition state substance, it has the property that the enzyme can efficiently and exclusively catalyze chemical reactions under mild conditions. By analogy, if an antibody can bind to a transition-state analog, it will also bind to the transition-state species in the chemical reaction process, and such an antibody has catalytic properties.