Immunochemical studies of an organ-specific thermostable antigen of bovine brain.

The physical and chemical nature of the bovine brain BE antigen was studied, along with antigenic studies to verify the organ-specificity characteristics. These preparations were found to be quite heterogeneous physico-chemically, containing nucleic acids, carbohydrates, protein and possible lipid constituents. The extinction coefficients were found to be 12.0 (at 280 mμ) and 2.2 (at 540 mμ, biuret). Ultracentrifugal analysis revealed three major components, with extrapolated sedimentation coefficients of 8.60, 2.20 and 1.80. Electrophoretic analysis showed six (or more) components. Because of the heterogeneity chemical classification of the actual brain-specific antigen was determined by degradative studies, using chymotrypsin and periodate. Based on thermostability, a carbohydrate content of 4.6 per cent, and destruction by dilute chymotrypsin, the brain-specific antigenic component has been tentatively classified as a mucoprotein.