Each glycoprotein (10 µg) was added to 50 mM ammonium bicarbonate, and SmE was added in a 1:10 ratio of enzyme:protein prior to incubation overnight at 37 °C. Samples were reduced with DTT (2 mM) at 65 °C for 20 minutes, then alkylated with IAM (5 mM) at room temperature in the dark for 15 min.