Table 2.

Characteristics of the peptides containing the CES1c active site serine (Ser221) that were found to be conjugated to SYD985

Precursor (1+)CES1c fragmentaLinker massResidual massSYD985 sequence
Light chain
828.04 (3+) 2482.131140.6618.28723.25FNRGEC
773.74 (3+) 2319.23979.5618.28723.30FNRGEC
741.32 (3+) 2221.98880.4618.28723.30FNRGEC
813.03 (3+) 2437.11880.4618.28938.43KSFNRGEC
684.32 (4+) 2734.28880.4618.281235.60PVTKSFNRGEC
Heavy chain
836.39 (4+) 3342.55680.3618.282045.99THTC(NEM)PPCPAPELLGGPSVF
891.18 (4+) 3561.70880.4618.282064.02THTC(NEM)PPCPAPELLGGPSVF +H2O
1181.89 (3+) 3543.69880.4618.282046.01THTC(NEM)PPCPAPELLGGPSVF
  • aCES1c peptide fragments (uncharged): 680.3 = GESSGG; 880.4 = GESSGGIS; 979.5 = GESSGGISV; 1140.6 = IFGESSGGIS. “+H2O” refers to hydrolysis (ring opening) of the maleimide moiety in the linker drug.