Figure 1. Neprilysin-like peptidase activity in vitreous samples

Neprilysin-like peptidase activity was measured in vitreous samples obtained from patients with macular hole (Control) or proliferative diabetic retinopathy (Patient). A: Representative chromatograms for measurement of neprilysin activity. Arrows indicate the product, Dansyl-D-Ala-Gly. B: Peptidase activity in the absence (open column) or presence (solid column) of thiorphan was measured by means of an HPLC-fluorometric system, as described under Materials and Methods. C: Neprilysin-like peptidase activity was calculated by subtraction of thiorphan-insensitive peptidase activity from total activity. Values are mean±SEM, n=8 (Control) and 10 (Patient). Asterisk (*) represents p<0.001 (Student t-test).