Figure 3.

Evaluation of chemoselectivity of the TACO reaction. (a) Chemoselectivity studies of the TACO reaction with varying tripeptides FXV, where X = K, Kme, Kme₂, H, D, S, M, Y, C, R, N, and W. Only the Kme₂ residue modified to an aldehyde under the reaction conditions. Side adducts were observed with histidine (fluorination), methionine (sulfoxide), tryptophan (fluorination and oxygenation), and cysteine (disulfide). (b) Selective derivatization of Kme₂-generated aldehydes on tripeptides FKme₂X, where X = M, H, W, and C, in the presence of side adducts on histidine, methionine, cysteine, and tryptophan using oxime and thiazolidine chemistry in NaP buffer. The presence of TACO-generated adducts did not interfere with subsequent modification of dimethyl lysine sites, thus indicating the negligible effect of the adducts on downstream application of TACO for profiling of lysine dimethylome.