Antiferments

Antiferments, substances that inhibit the action of enzymes. A number of simpler chemical compounds (for example, salts of heavy metals, HCN, certain alkaloids, etc.) that have a similar effect are conventionally called "enzyme poisons," leaving the term A. for substances of biological origin and undefined chemical structure. A., apparently, mostly belong to proteins, sometimes perhaps to lipoids. Along with A. found in various tissues and organs under normal conditions, there are A. that form in the body when the corresponding enzyme is introduced from outside, i.e., to a certain degree analogous to antitoxins and other antibodies. Individual A. differ in greater or lesser specificity, acting only on a specific enzyme or a limited group of enzymes. The mechanism of action of A. can apparently be quite varied. In many cases, one must think of the adsorption of the enzyme onto colloidal particles of A., if such adsorption is accompanied by the binding of the active chemical group of the enzyme molecule. In other cases, actual chemical interaction between A. and the active group of the enzyme is also possible. Undoubtedly, very often the action of A. is directed not at the enzyme itself, but at the so-called accompanying substances closely associated with the enzyme molecule, which only secondarily involve the enzyme in the reaction, as a result of which its activity decreases. This particularly applies to A. obtained by immunization. The action of A. is mostly reversible; they do not destroy the enzyme molecule but only temporarily inactivate it. This follows from the biological significance of A.: by binding enzymes, they regulate the course of chemical processes in the cell. The presence of A. in the cell protects the cell components from being broken down by the enzymes contained in it. The same role is played by A. found in the tissues of parasites that inhabit the gastrointestinal tract: A. protect these parasites from being digested by digestive juices. Among individual A., we note antilab (inhibiting the action of rennet), one of the first studied A., contained in serum, milk; antitrypsin (see) - in serum, yeast cells, parasites. v. Engelhardt.