Fig. 5.

The effect of His-Tyr and His-His on hydrolysis of bradykinin, angiotensin I, and neurotensin by Nln. Recombinant rat Nln (0.5 nM) was incubated with one of the endogenous peptides (20 µM) in the absence or presence of His-Tyr or His-His (40 or 100 µM). Formation of neurotensin-(1-10) [NT-(1-10)], angiotensin-(1-7) [Ang-(1-7)], and bradykinin-(1-5) [BK-(1-5)] was documented by mass-spectrometry analysis (n = 4 independent experiments with duplicate samples for controls and individual samples for each concentration of either dipeptide; ***, P < 0.001 in comparison with Nln alone). In all panels, “0 and Nln (–)” corresponds to a condition wherein the respective peptide substrate was incubated in assay buffer alone (i.e., no Nln, hence no product formation). Likewise, “0 with Nln (+)” corresponds to a condition wherein the respective peptide substrate was incubated in assay buffer with Nln alone (i.e., no activator molecule was present, corresponds to basal level of product formation). The black line within the scattered dots for each experimental group indicates the mean.