Product Overview

The sequence of this product is derived from Streptoverticillium mobaraense, and is recombinantly expressed in E. coli. It catalyzes an acyl transfer reaction between the γ-carboxamide groupe of glutamine (Gln) and the ε-amino group of lysine (Lys) residues to form a stable amide bond, thereby inducing covalent cross-linking and polymerization between and within protein molecules. Unlike transglutaminases (TG enzymes) of animal origin, the catalytic activity of this product does not require the presence of Ca²⁺. The optimal pH range for the enzyme's reaction is pH7.0–7.5, and the optimal temperature for enzyme activity is 45–50°C. Both commonly used PB buffer and HEPES buffer are applicable, while buffer systems containing amino groups should be avoided in the coupling reaction.

Key Features

Recombinant microbial origin

Derived from Streptoverticillium mobaraense and recombinantly expressed in E. coli, providing a non-animal source of transglutaminase suitable for bioconjugation workflows.

Calcium-independent activity

Unlike animal-derived transglutaminases, this enzyme does not require Ca²⁺ for catalytic activity, simplifying reaction conditions in protein modification processes.

Defined enzymatic specificity

Catalyzes acyl transfer between the γ-carboxamide group of glutamines (Gln) and the ε-amino group of lysine (Lys), forming stable ε-(γ-glutamyl) lysine isopeptide bonds for covalent cross-linking and protein conjugation.

High purity and activity

Enzyme specific activity is >30 U/mg, with purity ≥95% as determined by SEC-HPLC.

Compatible reaction conditions

Shows optimal activity at pH 7.0–7.5 and 45–50 °C. Compatible with common buffers such as PBS and HEPES; buffers containing primary amines should be avoided due to potential interference with the coupling reaction.

Applications

Protein conjugation and modification

Used for site-independent or semi-directed modification of proteins, including antibodies and other biomolecules, through enzymatic cross-linking.

Protein labeling and immobilization

Applicable for covalent labeling and surface immobilization of proteins in biochemical assays and analytical platforms.

Bioconjugation in XDC development

Widely used in enzyme-mediated conjugation strategies for antibody–drug conjugates (ADC), protein–drug conjugates (PDC), antibody–oligonucleotide conjugates (AOC), and related XDC formats.

Protein cross-linking and polymerization

Supports controlled cross-linking and polymerization of proteins for research and material science applications.

Performance Data

Purity by SDS-PAGE

Purity by SEC-HPLC

FAQ

What is the role of mTGase in ADC development?

mTGase is a key enzyme for site-specific conjugation of antibody-drug conjugates (ADCs). It specifically recognizes the glutamine residues (especially the Q295 site) on the antibody Fc region, and catalyzes the formation of stable amide bonds between amine-containing linkers-toxins and antibodies, thereby yielding highly homogeneous ADCs.

Compared with conventional random conjugation methods (such as lysine or cysteine conjugation), mTGase-mediated site-specific conjugation produces ADCs with uniform Drug-to-Antibody Ratio (DAR), which greatly improves the pharmacokinetic properties and therapeutic index of ADCs.

What are the prerequisites for mTGase-mediated site-specific conjugation?

For mTGase to act on the antibody Q295 site, the N-linked glycan at the N297 site of the antibody Fc region must be removed. Native N-glycans cause steric hindrance and block mTGase from accessing the Q295 site. Therefore, glycosidases (e.g., Endo S or PNGase F) are generally used first to remove glycans and expose the Q295 site for effective catalysis by mTGase.

What DAR values can be achieved via mTGase-mediated ADC conjugation?

One antibody molecule has two modification sites available via mTGase (one Q295 site on each heavy chain). For higher DAR values (e.g., DAR 4 or DAR 6), branched linker technology is adopted: branched linkers are first conjugated to the Q295 site, and each branch can be further linked to one toxin molecule.

Key advantages of using mTGase for ADC conjugation

• High DAR homogeneity: Site-specific conjugation produces structurally uniform ADCs and eliminates batch-to-batch variation seen in traditional methods.

• Intact antibody structure: mTGase targets the Q295 site without impairing the antigen-binding capability of antibodies.

• Excellent stability: The formed amide bond is stable, enabling favourable serum stability of ADCs.

• Scalable process: Reactions proceed under mild conditions, suitable for large-scale manufacturing.