The amounts of the B2 receptor-interacting peptides in the Sap-digested LK samples. LK samples (1.5 μM) were digested with 0.03 μM Sap in the citrate buffer (pH 5.0) at 37°C for 6 or 24 hours, the reaction was stopped using pepstatin A (at a final concentration of 10 μM), and the samples were analyzed for kinin content using a competitive radioreceptor assay that used B2 receptor-overexpressing HEK293 cells. The calibration plot for the assay was prepared using a bradykinin standard. The results are corrected by subtracting the values, determined in the undigested LK sample. Data represent mean values from three separate radioreceptor binding analyses (three independently prepared cultures of B2 receptor-bearing cells), with the measurements performed in triplicates within each experiment. The error bars represent the standard deviations; asterisks denote the statistical significance of the differences between Sap-treated and undigested LK samples (t-Student test, p < 0.05).