Lipase from porcine pancreas type 6 s

Glucose, o-phenylenediamine, Glucose oxidase, human serum albumin, and lipase from porcine pancreas type VI-S were purchased from Sigma-Aldrich (Saint Louis, Missouri, United States) with activity 20,000 U per protein mg (activity 1 U is equal to hydrolysis of 1.0 microequivalent of fatty acid from a triglyceride in 1 hour at pH 7.7 at 37°C using olive oil). Citric acid, sodium hydroxide, ethanol, and formaldehyde were obtained from Penta (Prague, Czech Republic). The organic and inorganic reagents used in these experiments were of analytical grade. Deionized water was prepared using the Aqua Osmotic 02 device by Aqua Osmotic, Tisnov, Czech Republic.

All chemicals were obtained from commercial sources in analytical grade, and no adjustment was done on chemicals before use. Indoxyl acetate (IA), phosphate-buffered saline (pH 7.4), Tween 20, lipase from porcine pancreas (Type VI-S, ≥20,000 units/mg protein, lyophilized powder), tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl), CaCl₂, and Tween 20 were bought from Sigma-Aldrich (St. Louis, MO, USA), and absolute ethanol was purchased from Penta (Prague, Czech Republic). Lipase buffer was composed from 20 mmol/l Tris-HCl, 80 mmol/l CaCl₂, and 1% Tween 20. Temperature of all chemicals was adapted to laboratory conditions, and all experiments were performed under standard ambient temperature and pressure (SATP).