Figure 4.

Oxidative stress does not modulate the esterase activity of pancreatic porcine lipase. (A) Representative enzymatic kinetic curves of esterase activity from purified porcine pancreatic lipase as spectrophotometrically monitored by the appearance of pNP (Absorbance at 403 nm) at the indicated substrate concentrations (pNPA) pretreated with vehicle buffer alone (control) or with 100 µM H₂O₂. Note that pre-treating pancreatic porcine lipase with H₂O₂ does not alter its esterase activity towards pNPA. The experiment shown in this figure is representative of two independent experiments with similar results; (B) Representative enzymatic kinetic curve of porcine lipase pretreated with H₂O₂, based on the initial velocities (V₀) obtained from the data shown in A suggests that H₂O₂ does not modulate the esterase activity of pancreatic porcine lipase; (C) Representative enzymatic kinetic curves of esterase activity from purified porcine pancreatic lipase as spectrophotometrically monitored by the appearance of pNP (OD of 403 nm) at the indicated substrate concentrations (pNPA) pretreated with vehicle buffer alone (control), or with 2 mM IAA. Note that IAA treatment does not significantly decrease the esterase activity of pancreatic porcine lipase.