Fig. 3.

Cyt c at concentrations reported to be found in normal serum does not inhibit LRG detection in the ELISA as shown in a competitive experiment in which increasing concentrations of soluble Cyt c inhibit the binding of LRG (present in 1% serum) to plate-bound Cyt c (A). LRG is not the only serum protein adsorbed on Cyt c-Affi-gel 10 (B), but is the only Cyt c-binding serum protein that binds specifically to native Cyt c and is recognized by mAb 2F5.A2 (see text). Proteins in sera pooled from control subjects and from TSS patients (1 ml total) were adsorbed on horse Cyt c-Affi-gel and eluted, visualized by SDS-PAGE, and identified by mass spectrometry (see the text). Hemopexin binds the exposed heme in denatured Cyt c, while plasmin likely adsorbed to the affinity column due to its affinity for lysine residues.