Figure 2.
Comparison of stability and reactivity of triazolyl-tetrazine 3b with other tetrazines. (A) Structures of the tetrazines and TCOs in this stability and reactivity study. (B) The stability of the tetrazines was evaluated in DMEM containing 10% FBS at 37 °C. (C) Second-order rate constants for the reactions of H-Tz-A,443b, Py-Tz, Me-Tz, and Ph-Tz with 4a-TCO in PBS at 37 °C. (D) Correlation between the metabolic stability (residual fraction after 24 h incubation in DMEM) and reactivity of tetrazines. (E) Second-order rate constant for the reaction of 3b with d-TCO in PBS at 23 °C.