DT3C is a recombinant fusion protein composed of the diphtheria toxin (DT) lacking its receptor-binding domain, fused to the C1,

C2, and C3 IgG-binding domains of Streptococcal protein G. This protein binds with high affinity to the Fc region of antibodies.

Upon internalization into cells along with the antibody, DT3C is cleaved by intracellular furin protease, releasing the toxic DT

moiety. DT inhibits EF2 through ADP-ribosylation, thereby blocking intracellular protein synthesis and ultimately inducing cell

death. Free DT3C that does not enter cells lacks cytotoxic activity. Therefore, the extent of cell killing directly reflects the

efficiency of antibody internalization.

This product is expressed in Escherichia coli, comprises amino acids 33-417 (P00588) and 291-497 (P19909), contains an

N-terminal 6×His tag, has a molecular weight of 69 kDa, a purity of ≥90% (SDS-PAGE), a concentration of 1 mg/ml, and an

endotoxin level of <1 EU/μg.

The use of recombinant DT3C protein is straightforward: simply incubate DT3C with the target antibody for 30 minutes to form

the Ab-DT3C complex. This complex requires no further processing and can be directly added to cells in complete culture medium

for incubation. In vitro, it functions analogously to antibody-drug conjugates (ADCs), delivering the cytotoxic effects of diphtheria

toxin to specific cells through internalization, thereby enabling the assessment of antibody internalization efficiency.

at -70°C or below for one year, at -18°C or below for one month, and at 2°C-8°C for two weeks. Avoid repeated

freeze-thaw cycles. It is recommended to aliquot the product into smaller portions and store at -70°C or below.