Myeloperoxidase activity assay kit

RIPA lysis buffer was used for lysing lung tissues, and 10-mg tissue samples were taken for each test sample. After washed with cold PBS, the tissues were resuspended in 4 volumes of MPO assay buffer, and then centrifuged (13,000×g for 10 min, 4 °C). The supernatant was collected and transferred to clean tubes which were placed on the ice. The MPO activity was assayed using Myeloperoxidase Activity Assay Kit (Abcam, ab105136), by measuring the absorbance of the sample at 460 nm using a microplate reader (Bio-Rad Laboratories, Hercules, CA, USA). The specific MPO activity in the lungs was expressed as unit/mg protein.

To measure the activity of myeloperoxidase, we used myeloperoxidase activity assay kit (Abcam ab105136; Cambridge, UK). The colons of mice were homogenized and resuspended in MPO assay buffer. The samples were centrifuged at 13,000× g for 10 min and collect the supernatant. The MPO substrate was added with supernatant in 96-well plate. TNB solution was mixed and incubated 5 to 10 min. The plate was measured at 412 nM using MMR SPARK^® Microplate Reader (Männedorf, Switzerland). All assays were performed as recommended by the manufacturer.

Radioimmunoprecipitation assay (RIPA) lysis buffer (BIOSYNTHESIS BIOTECHNOLOGY Co., Ltd., Beijing, China) was used to lyse tissues, and 10 mg tissue was obtained for each sample. Following washing with cold PBS, the tissues were resuspended in 9 volumes of PBS (included in the myeloperoxidase Activity Assay Kit) and then centrifuged at 4°C and 2,500 r/min for 10 min. The supernatant was collected and transferred to a clean tube, which was then placed on ice. Myeloperoxidase (MPO) activity was assayed using the myeloperoxidase Activity Assay Kit (Abcam Co., Ltd., Cambridge, United States) with measurement of the absorbance of the sample at 460 nm using a microplate reader. The specific MPO activity in the colon was measured as units/g (U/g) protein.