How do you calculate lysozyme activity of the serum?

Answer 1

blood samples were centrifuged at 7000g for 10 minutes and separated sera were frozen at -20"C until used for Liszt assay. Lysozyme level in blood samples was determined by the turbidimetric assay according to the method described by Ellis (1990) with slight modifications. Briefly, aliquots (1.75 ml) of

Micrococcus lysodeikticus suspension (Sigma) (0.375 mg/ml, 0.05 M sodium phosphate buffer, pH 6.2) was mixed with 250L of each sample and the

optical density was measured after 15 and 180 seconds by spectrophotometer (Biophotometer Eppendorf) at 670 nm wavelength. PBS was used as the blank and results were expressed in amounts of lysozyme (g) per one milligram of sample calibrated using a standard cure determined with hens egg white lysozyme (Sigma) in PBS.