Figure 5.

Effect of trypsin treatment on the activity in spleen homogenate. (A) Spleen homogenate (2 mg/ml) was treated with trypsin (20 μg/ml) at 37°C for the indicated times (min) or without trypsin for 60 min (-T). After addition of excess soybean trypsin inhibitor (100 μg/ml), samples were incubated with nitrated BSA for 10 min. Additional controls included nitrated BSA incubated without other additions (N-B) or with trypsin plus soybean trypsin inhibitor (N-B, T+I). (B) Coomassie brilliant blue stain of a transferred membrane from the experiment of A. Lanes correspond to those of A. (C) Effect of trypsin on the spleen denitrating activity as a function of time. Values are means ± SD of experiments with five different homogenates.