In enzyme conjugate, TGs can be used to conjugate small molecules onto antibodies Gln residues, for instance Q295 on IgG, to form ADCs with a potential DAR of 2. The removal or size reduction of N297 glycans is prerequisite to reduce spacial hindrance for TG activity. Alternatively, a mutation that converts N297 to Q also facilitates the TG-mediated conjugation and results in ADCs with a potential DAR of up to 4. https://www.creative-biolabs.com/adc/enzyme-mediated-modification-and-conjugation.htm