Time course of ³H-α-chain degradation. Replicate proteolysis reaction mixtures contained a hemolysate from the blood cells of donor C.G. (A) or S.D. (B) and were incubated at 37°C for either 0, 15, 30, 60, 90, or 120 minutes. Mixtures contained ATP, an ATP-regenerating system, supplementary Ub, and either no Ubal (○), 0.8 μmol/L Ubal (A, •), or 1.0 μmol/L Ubal (B, •). Data also are shown from the corresponding mixtures without added ATP and ± Ubal (▴ and ▵, respectively; note that unfilled symbols may be obscured by overlap with filled symbols). Each data point represents the average from duplicate reaction mixtures.