Fig. 2.

Inactivation of DAF’s function by nonenzymatic glycation. Purified E^hu DAF (20 g/ml) was incubated with either 0.5 M ribose (open circle) or buffer (control; closed circle) as described in Methods. Following incubation of this modified DAF protein with antibody-sensitized guinea pig erythrocytes (E^gpA), the erythrocytes were incubated with increasing percentages of human serum (containing complement), and lysis quantitated. Whereas hemolysis of E^gpA, was reduced by native non-glycated DAF, hemolysis of E^gpA treated with glycated DAF was nearly identical to that of untreated E^gpA control not exposed to DAF (closed triangles).