FIGURE 3.

Proof-of-principle; ABP labeling of GBA. a, overexpressed myc/His-tagged GBA variants in total COS-7 cells with excess ABP 1 or ABP 2 and subsequently purified via His-tag pulldown. Labeling with ABP 1 in the absence/presence of sodium azide (first, second gel), idem with ABP 2 (third and fourth gel), and GBA detected with α-myc (fifth gel). b, β-epoxide 1 and β-aziridine 2 labeling at different sodium azide concentrations. c, rescue of labeling with small acids. Labeling of wild-type GBA and acid/base mutants E235G and E235Q at pH 5.2 with β-epoxide 1 in the absence or presence of 1 m sodium azide (forms hydrazoic acid (HN₃)), 10 m acetic acid (HAc), or 15 m formic acid (HFo), and subsequently purification via His-tag pulldown is shown. Inter-gel comparisons facilitated by excess imiglucerase labeled with 50 fm ABP 1 (asterisk) as positive control.