The Chemistry of TG Enzyme: Understanding Protein Cross-Linking Reactions

In the fields of food science, pharmaceutics, and biotechnology, TG enzyme (glutamine transaminases) is of interest due to its unique catalytic ability. Especially in protein cross-linking reactions, TG enzyme exhibits remarkable chemical properties. In this article, we will bring you an in-depth understanding of the chemical properties of TG enzyme and discuss its application in protein cross-linking reactions.

Basic Introduction of TG Enzyme

TG enzyme, known as glutamine transaminase, is an enzyme that can catalyse the cross-linking reaction between protein molecules. It belongs to the family of protein cross-linking enzymes, which link different protein molecules together by transferring glutamine groups to form new protein structures. TG enzyme is widely found in living organisms, such as animal muscle, liver, pancreas, and other tissues, and also in some microorganisms.

The Chemical Properties of TG Enzyme

Catalytic Specificity

TG enzyme has a high degree of catalytic specificity in that it catalyzes only the transfer reaction of the glutamine moiety, but not other types of amino acid transfer reactions. This specificity gives TG enzyme a unique advantage in protein cross-linking reactions.

Reaction Conditions

TG enzyme requires certain reaction conditions when catalysing protein cross-linking reactions. Usually, it needs to be under the appropriate temperature, pH, and ionic strength to exert the best catalytic effect. In addition, certain metal ions such as calcium and magnesium ions may also have an effect on the activity of TG enzyme.

Reversibility

Unlike some other enzymes, the protein cross-linking reaction catalysed by TG enzyme is usually irreversible. Once a cross-linked structure is formed between protein molecules, it is very difficult to unwind it by simple physical or chemical means. This irreversibility makes TG enzyme unique in the food industry.

The Mechanism of Protein Cross-linking Reaction

In protein cross-linking reaction, TG enzyme joins two or more protein molecules together by transferring glutamine groups. This cross-linking reaction can change the structure and properties of proteins, giving them better stability, elasticity, and palatability. Specifically, the mechanism of action of protein cross-linking reaction is as follows:

Improved Stability

Through protein cross-linking reaction, a tighter protein network structure can be formed, thus enhancing the water retention and stability of the food. This stability makes the food less likely to deteriorate during storage and transport.

Enhancement of Elasticity and Taste

Protein cross-linking reaction can increase the interaction force between protein molecules, so that the food has better elasticity and taste. For example, in meat processing, TG enzyme can improve the texture and taste of meat products, making them more tender and juicy.

Innovative food development: Innovative food products with specific taste, texture, and nutritional value can be developed by utilizing the catalytic properties of TG enzyme. For example, using TG enzyme to make vegetarian substitutes, low-fat and high-protein foods, etc.

Application of TG Enzyme in Food Industry

Due to its unique catalytic ability and chemical properties, TG enzyme has been widely used in the food industry. The following are some examples of the application of TG enzyme in food industry:

Meat Processing

In meat processing, TG enzyme can improve the texture and taste of meat products, making them firmer and more elastic. In addition, TG enzyme can also improve the water retention and stability of meat products and extend the shelf life.

Soybean Processing

In soybean processing, TG enzyme can mimic the texture and taste of animal proteins, giving soybean products a better eating quality. For example, soybean products such as dried tofu and vegetarian chicken made with TG enzyme have similar taste and nutritional value as animal meat products.

Dairy Processing

In dairy processing, TG enzyme can improve the texture and taste of cheese, yoghurt, and other products. By catalysing the cross-linking reaction of proteins, TG enzyme can make cheese firmer and more elastic; make yoghurt more delicate and smooth.

In conclusion, as a unique biocatalyst, TG enzyme shows its unique chemical properties and application value in protein cross-linking reaction. With the progress of science and technology and people's continuous pursuit of food quality, the application of TG enzyme in the food industry will become more and more extensive.