The proteinaceous nature of BLIS was determined by well
diffusion assay method. 30 mL of Trypsin (1 mg/mL) and Proteinase
K (1 mg/mL) were poured in a well next to a well containing active
CFS. The diffusion of protease produced the inactivation of BLIS and
the resulting truncation of the inhibition halo occurred after incubation
overnight at 37 C.