Figure 1.

Separation of HEWL labeled with methylene carbene by RP-HPLC. Photolabeled HEWL eluted after size-exclusion chromatography (see Materials and Methods, “Photolabeling of free HEWL and HEWL complexed With IgG₁ D1.3”) was sampled onto an analytical C4 column. Panels a and b correspond to HEWL labeled in its free or complexed form, respectively. Elution was monitored by UV absorption at 280 nm (solid line) and by measurement of the radioactivity associated to each collected fraction (gray bars). The inset table (b) shows the radioactivity incorporated to each HEWL sample expressed as mmol CH₂/mol protein at 1 mM DZN.