Measurement of Pancreatic Lipase Activity. The pancreatic lipase activity was measured using 4-methylumbelliferyl oleate (4-MU oleate) as a substrate (30). Twenty-five microliters of a sample solution dissolved in water and 50 μL of a 0.1 mM 4-MU solution dissolved in a buffer consisting of 13 mM Tris-HCl, 150 mM NaCl, and 1.3 mM CaCl2 (pH 8.0) were mixed in the well of a microtiter plate, and 25 μL of the lipase solution (50 U/mL) in the above buffer was then added to start the enzyme reaction. After incubation at 25 °C for 30 min,0.1 mL of 0.1 M sodium citrate (pH 4.2) was added to stop the reaction.The amount of 4-methylumbelliferone released by lipase was measured with a fluorometrical microplate reader (Fluoroskan Ascent C Lab-systems, Inc.) at an excitation wavelength of 355 nm and an emission wavelength of 460 nm. The IC50 of the test sample was obtained from the least-squares regression line of the plots of the logarithm of the sample concentration (log) versus the pancreatic lipase activity (%).
Preparation of Crude Polyphenol Oxidase Solution. Fresh leaves(600 g) of C. sinensis cV. Kyoken-129gou and polyamide (150 g) were homogenized in a 0.01 M potassium phosphate buffer (pH 7.0) under cooling. After removal of the insolubles by filtration through gauze,the solution was centrifuged (5000 rpm), and the supernatant was treated with acetone at -20 °C. The resulting precipitates were collected using an 8000 rpm centrifuge, dissolved in 600 mL of a 0.01 M citric acid-0.02 M potassium phosphate buffer (pH 5.6), and used for the enzymatic reaction of polyphenol oxidase.
Measurement of Pancreatic Lipase Activity. The pancreatic lipase activity was measured using 4-methylumbelliferyl oleate (4-MU oleate) as a substrate (30). Twenty-five microliters of a sample solution dissolved in water and 50 μL of a 0.1 mM 4-MU solution dissolved in a buffer consisting of 13 mM Tris-HCl, 150 mM NaCl, and 1.3 mM CaCl2 (pH 8.0) were mixed in the well of a microtiter plate, and 25 μL of the lipase solution (50 U/mL) in the above buffer was then added to start the enzyme reaction. After incubation at 25 °C for 30 min,0.1 mL of 0.1 M sodium citrate (pH 4.2) was added to stop the reaction.The amount of 4-methylumbelliferone released by lipase was measured with a fluorometrical microplate reader (Fluoroskan Ascent C Lab-systems, Inc.) at an excitation wavelength of 355 nm and an emission wavelength of 460 nm. The IC50 of the test sample was obtained from the least-squares regression line of the plots of the logarithm of the sample concentration (log) versus the pancreatic lipase activity (%).
Preparation of Crude Polyphenol Oxidase Solution. Fresh leaves(600 g) of C. sinensis cV. Kyoken-129gou and polyamide (150 g) were homogenized in a 0.01 M potassium phosphate buffer (pH 7.0) under cooling. After removal of the insolubles by filtration through gauze,the solution was centrifuged (5000 rpm), and the supernatant was treated with acetone at -20 °C. The resulting precipitates were collected using an 8000 rpm centrifuge, dissolved in 600 mL of a 0.01 M citric acid-0.02 M potassium phosphate buffer (pH 5.6), and used for the enzymatic reaction of polyphenol oxidase.
การแปล กรุณารอสักครู่..
