White to light yellow to dark brown powder or granule, or a clear light yellow to dark brown liquid. Soluble in water, insoluble in ethanol, hygroscopic. It can convert α-glutamyl group in protein peptide into ε-amino group of lysine residue in peptide. Transglutaminase catalyzes the cross-linking reaction, which modifies the protein and improves the plasticity, water-holding, water-solubility and functionality of the protein, and as a protein modifier there is a great application prospect in the food industry. At present, it is widely used in meat products, dairy products and plant protein products to improve the quality of the products. In noodle processing, the addition of transglutaminase can promote the cross-linking between other proteins and gluten proteins, improve the organizational structure of gluten network, and thus improve the quality of finished noodles.
Transglutaminase has been used in a study to improve quantifiable assays to fully characterize the role of transglutaminase in diseases such as Huntington′s disease and Alzheimer′s disease.Transglutaminase has also been used in a study to develop a nonradioactive dot blot assay for transglutaminase activity.
Transglutaminase from guinea pig liver consists of a single polypeptide chain of 691 amino acid residues. It has six potential glycosylation sites (Asn-X-Ser or Asn-X-Thr), but it is not glycosylated. The molecular mass is approximately 76.6 kDa. It is calcium dependent and has several calcium binding sites. The enzyme is inhibited by iodoacetamide and N-ethylmaleimide in the presence of calcium. It catalyzes the incorporation of small molecular weight amines into γ-glutamine sites of proteins. In the absence of small molecular weight amines, it catalyzes the cross linking of proteins that results in the formation of γ-glutamyl-ε-lysine side chain peptides. Liver transglutaminase is a nonzymogenic enzyme.
